diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index f0cd08796e6..6fbacad1911 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -3,7 +3,9 @@
 
 name: Node.js CI
 
-on: [pull_request]
+on:
+  pull_request:
+  workflow_call:
 
 permissions:
   contents: read
diff --git a/.github/workflows/keyboard_plugin_test.yml b/.github/workflows/keyboard_plugin_test.yml
deleted file mode 100644
index e64efe983c6..00000000000
--- a/.github/workflows/keyboard_plugin_test.yml
+++ /dev/null
@@ -1,66 +0,0 @@
-# Workflow for running the keyboard navigation plugin's automated tests.
-
-name: Keyboard Navigation Automated Tests
-
-on:
-  workflow_dispatch:
-  pull_request:
-  push:
-    branches:
-      - main
-
-permissions:
-  contents: read
-
-jobs:
-  webdriverio_tests:
-    name: WebdriverIO tests
-    timeout-minutes: 10
-    runs-on: ${{ matrix.os }}
-
-    strategy:
-      fail-fast: false
-      matrix:
-        os: [ubuntu-latest]
-
-    steps:
-      - name: Checkout core Blockly
-        uses: actions/checkout@v5
-        with:
-          path: core-blockly
-
-      - name: Checkout keyboard navigation plugin
-        uses: actions/checkout@v5
-        with:
-          repository: 'google/blockly-keyboard-experimentation'
-          ref: 'main'
-          path: blockly-keyboard-experimentation
-
-      - name: Use Node.js 20.x
-        uses: actions/setup-node@v5
-        with:
-          node-version: 20.x
-
-      - name: NPM install
-        run: |
-          cd core-blockly
-          npm install
-          cd ..
-          cd blockly-keyboard-experimentation
-          npm install
-          cd ..
-
-      - name: Link latest core main with plugin
-        run: |
-          cd core-blockly/packages/blockly
-          npm run package
-          cd dist
-          npm link
-          cd ../../../../blockly-keyboard-experimentation
-          npm link blockly
-          cd ..
-
-      - name: Run keyboard navigation plugin tests
-        run: |
-          cd blockly-keyboard-experimentation
-          npm run test
diff --git a/.github/workflows/publish.yml b/.github/workflows/publish.yml
new file mode 100644
index 00000000000..0f403f4479a
--- /dev/null
+++ b/.github/workflows/publish.yml
@@ -0,0 +1,137 @@
+name: Publish to npm
+
+on:
+  workflow_dispatch:
+    inputs:
+      dry_run:
+        description: 'Dry run - print the version that would be published, but do not commit or publish anything.'
+        required: false
+        default: false
+        type: boolean
+      skip_versioning:
+        description: >
+          Skip version bump - use the version already in the repo
+          (e.g. retry after npm publish failed but the release commit is already pushed).
+        required: false
+        default: false
+        type: boolean
+
+permissions:
+  contents: write
+  id-token: write
+
+jobs:
+  ci:
+    uses: ./.github/workflows/build.yml
+
+  version:
+    needs: ci
+    runs-on: ubuntu-latest
+    timeout-minutes: 30
+    outputs:
+      version: ${{ steps.version.outputs.version }}
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v5
+        with:
+          fetch-depth: 0
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v5
+        with:
+          node-version: 24.x
+          registry-url: 'https://registry.npmjs.org'
+
+      - name: Install dependencies
+        if: ${{ !inputs.skip_versioning }}
+        run: npm ci
+
+      - name: Determine version bump
+        id: bump
+        if: ${{ !inputs.skip_versioning }}
+        working-directory: packages/blockly
+        run: |
+          RELEASE_TYPE=$(npx conventional-recommended-bump --preset conventionalcommits -t blockly-)
+          echo "release_type=$RELEASE_TYPE" >> "$GITHUB_OUTPUT"
+          echo "Recommended bump: $RELEASE_TYPE"
+
+      - name: Apply version bump
+        if: ${{ !inputs.skip_versioning }}
+        working-directory: packages/blockly
+        run: npm version ${{ steps.bump.outputs.release_type }} --no-git-tag-version
+
+      - name: Read package version
+        id: version
+        working-directory: packages/blockly
+        run: |
+          VERSION=$(node -p "require('./package.json').version")
+          echo "version=$VERSION" >> "$GITHUB_OUTPUT"
+          echo "Version: $VERSION"
+
+      - name: Upload versioned files
+        if: ${{ !inputs.skip_versioning }}
+        uses: actions/upload-artifact@v4
+        with:
+          name: versioned-files
+          path: |
+            packages/blockly/package.json
+            package-lock.json
+
+  publish:
+    needs: version
+    runs-on: ubuntu-latest
+    if: ${{ !inputs.dry_run }}
+    environment: release
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v5
+        with:
+          fetch-depth: 0
+          ssh-key: ${{ secrets.DEPLOY_PRIVATE_KEY }}
+
+      - name: Download versioned files
+        if: ${{ !inputs.skip_versioning }}
+        uses: actions/download-artifact@v4
+        with:
+          name: versioned-files
+
+      - name: Commit and push version bump
+        if: ${{ !inputs.skip_versioning }}
+        run: |
+          git config user.name "github-actions[bot]"
+          git config user.email "41898282+github-actions[bot]@users.noreply.github.com"
+          git add packages/blockly/package.json package-lock.json
+          git commit -m "release: v${{ needs.version.outputs.version }}"
+          git push
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v5
+        with:
+          node-version: 24.x
+          registry-url: 'https://registry.npmjs.org'
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Build package
+        working-directory: packages/blockly
+        run: npm run package
+
+      - name: Publish to npm
+        working-directory: packages/blockly/dist
+        run: npm publish --verbose
+
+      - name: Create tarball
+        working-directory: packages/blockly
+        run: npm pack ./dist
+
+      - name: Create GitHub release
+        working-directory: packages/blockly
+        env:
+          GH_TOKEN: ${{ github.token }}
+        run: |
+          TARBALL="blockly-${{ needs.version.outputs.version }}.tgz"
+          gh release create "blockly-v${{ needs.version.outputs.version }}" "$TARBALL" \
+            --repo "$GITHUB_REPOSITORY" \
+            --title "blockly-v${{ needs.version.outputs.version }}" \
+            --generate-notes
diff --git a/.github/workflows/update-gh-pages.yml b/.github/workflows/update-gh-pages.yml
new file mode 100644
index 00000000000..e45aca688a9
--- /dev/null
+++ b/.github/workflows/update-gh-pages.yml
@@ -0,0 +1,36 @@
+# Manual workflow to update GitHub Pages from a chosen source branch.
+# The gulp updateGithubPages task builds the repo and force-pushes to gh-pages.
+
+name: Update GitHub Pages
+
+on:
+  workflow_dispatch:
+    inputs:
+      source_branch:
+        description: 'Source branch to build and deploy to GitHub Pages'
+        required: true
+        type: string
+        default: main
+
+permissions:
+  contents: write
+
+jobs:
+  update-gh-pages:
+    timeout-minutes: 15
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v5
+        with:
+          ref: ${{ inputs.source_branch }}
+          fetch-depth: 0
+
+      - name: Use Node.js
+        uses: actions/setup-node@v5
+        with:
+          node-version: 24.x
+
+      - name: Update GitHub Pages
+        working-directory: ./packages/blockly
+        run: npm run updateGithubPages:staging
diff --git a/package-lock.json b/package-lock.json
index 1eb2975365b..6d53d3e1949 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -514,6 +514,26 @@
         "node": ">=16"
       }
     },
+    "node_modules/conventional-changelog-preset-loader": {
+      "version": "4.1.0",
+      "resolved": "https://registry.npmjs.org/conventional-changelog-preset-loader/-/conventional-changelog-preset-loader-4.1.0.tgz",
+      "integrity": "sha512-HozQjJicZTuRhCRTq4rZbefaiCzRM2pr6u2NL3XhrmQm4RMnDXfESU6JKu/pnKwx5xtdkYfNCsbhN5exhiKGJA==",
+      "dev": true,
+      "license": "MIT",
+      "engines": {
+        "node": ">=16"
+      }
+    },
+    "node_modules/conventional-commits-filter": {
+      "version": "4.0.0",
+      "resolved": "https://registry.npmjs.org/conventional-commits-filter/-/conventional-commits-filter-4.0.0.tgz",
+      "integrity": "sha512-rnpnibcSOdFcdclpFwWa+pPlZJhXE7l+XK04zxhbWrhgpR96h33QLz8hITTXbcYICxVr3HZFtbtUAQ+4LdBo9A==",
+      "dev": true,
+      "license": "MIT",
+      "engines": {
+        "node": ">=16"
+      }
+    },
     "node_modules/conventional-commits-parser": {
       "version": "5.0.0",
       "resolved": "https://registry.npmjs.org/conventional-commits-parser/-/conventional-commits-parser-5.0.0.tgz",
@@ -533,6 +553,27 @@
         "node": ">=16"
       }
     },
+    "node_modules/conventional-recommended-bump": {
+      "version": "9.0.0",
+      "resolved": "https://registry.npmjs.org/conventional-recommended-bump/-/conventional-recommended-bump-9.0.0.tgz",
+      "integrity": "sha512-HR1yD0G5HgYAu6K0wJjLd7QGRK8MQDqqj6Tn1n/ja1dFwBCE6QmV+iSgQ5F7hkx7OUR/8bHpxJqYtXj2f/opPQ==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "conventional-changelog-preset-loader": "^4.1.0",
+        "conventional-commits-filter": "^4.0.0",
+        "conventional-commits-parser": "^5.0.0",
+        "git-raw-commits": "^4.0.0",
+        "git-semver-tags": "^7.0.0",
+        "meow": "^12.0.1"
+      },
+      "bin": {
+        "conventional-recommended-bump": "cli.mjs"
+      },
+      "engines": {
+        "node": ">=16"
+      }
+    },
     "node_modules/cosmiconfig": {
       "version": "9.0.0",
       "resolved": "https://registry.npmjs.org/cosmiconfig/-/cosmiconfig-9.0.0.tgz",
@@ -728,6 +769,24 @@
         "node": ">=16"
       }
     },
+    "node_modules/git-semver-tags": {
+      "version": "7.0.1",
+      "resolved": "https://registry.npmjs.org/git-semver-tags/-/git-semver-tags-7.0.1.tgz",
+      "integrity": "sha512-NY0ZHjJzyyNXHTDZmj+GG7PyuAKtMsyWSwh07CR2hOZFa+/yoTsXci/nF2obzL8UDhakFNkD9gNdt/Ed+cxh2Q==",
+      "deprecated": "This package is no longer maintained. For the JavaScript API, please use @conventional-changelog/git-client instead.",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "meow": "^12.0.1",
+        "semver": "^7.5.2"
+      },
+      "bin": {
+        "git-semver-tags": "cli.mjs"
+      },
+      "engines": {
+        "node": ">=16"
+      }
+    },
     "node_modules/global-directory": {
       "version": "4.0.1",
       "resolved": "https://registry.npmjs.org/global-directory/-/global-directory-4.0.1.tgz",
@@ -1471,7 +1530,7 @@
       }
     },
     "packages/blockly": {
-      "version": "12.4.1",
+      "version": "12.5.1",
       "hasInstallScript": true,
       "license": "Apache-2.0",
       "dependencies": {
@@ -1490,6 +1549,8 @@
         "async-done": "^2.0.0",
         "chai": "^6.0.1",
         "concurrently": "^9.0.1",
+        "conventional-changelog-conventionalcommits": "^7.0.2",
+        "conventional-recommended-bump": "^9.0.0",
         "eslint": "^9.15.0",
         "eslint-config-google": "^0.14.0",
         "eslint-config-prettier": "^10.1.1",
@@ -1503,11 +1564,8 @@
         "gulp-concat": "^2.6.1",
         "gulp-gzip": "^1.4.2",
         "gulp-header": "^2.0.9",
-        "gulp-insert": "^0.5.0",
         "gulp-rename": "^2.0.0",
         "gulp-replace": "^1.0.0",
-        "gulp-series": "^1.0.2",
-        "gulp-shell": "^0.8.0",
         "gulp-sourcemaps": "^3.0.0",
         "gulp-umd": "^2.0.0",
         "http-server": "^14.0.0",
@@ -6193,36 +6251,6 @@
         "xtend": "~4.0.1"
       }
     },
-    "packages/blockly/node_modules/gulp-insert": {
-      "version": "0.5.0",
-      "dev": true,
-      "license": "MIT",
-      "dependencies": {
-        "readable-stream": "^1.0.26-4",
-        "streamqueue": "0.0.6"
-      }
-    },
-    "packages/blockly/node_modules/gulp-insert/node_modules/isarray": {
-      "version": "0.0.1",
-      "dev": true,
-      "license": "MIT"
-    },
-    "packages/blockly/node_modules/gulp-insert/node_modules/readable-stream": {
-      "version": "1.1.14",
-      "dev": true,
-      "license": "MIT",
-      "dependencies": {
-        "core-util-is": "~1.0.0",
-        "inherits": "~2.0.1",
-        "isarray": "0.0.1",
-        "string_decoder": "~0.10.x"
-      }
-    },
-    "packages/blockly/node_modules/gulp-insert/node_modules/string_decoder": {
-      "version": "0.10.31",
-      "dev": true,
-      "license": "MIT"
-    },
     "packages/blockly/node_modules/gulp-rename": {
       "version": "2.1.0",
       "dev": true,
@@ -6246,48 +6274,6 @@
         "node": ">=10"
       }
     },
-    "packages/blockly/node_modules/gulp-series": {
-      "version": "1.0.2",
-      "dev": true,
-      "license": "MIT"
-    },
-    "packages/blockly/node_modules/gulp-shell": {
-      "version": "0.8.0",
-      "dev": true,
-      "license": "MIT",
-      "dependencies": {
-        "chalk": "^3.0.0",
-        "fancy-log": "^1.3.3",
-        "lodash.template": "^4.5.0",
-        "plugin-error": "^1.0.1",
-        "through2": "^3.0.1",
-        "tslib": "^1.10.0"
-      },
-      "engines": {
-        "node": ">=10.0.0"
-      }
-    },
-    "packages/blockly/node_modules/gulp-shell/node_modules/chalk": {
-      "version": "3.0.0",
-      "dev": true,
-      "license": "MIT",
-      "dependencies": {
-        "ansi-styles": "^4.1.0",
-        "supports-color": "^7.1.0"
-      },
-      "engines": {
-        "node": ">=8"
-      }
-    },
-    "packages/blockly/node_modules/gulp-shell/node_modules/through2": {
-      "version": "3.0.2",
-      "dev": true,
-      "license": "MIT",
-      "dependencies": {
-        "inherits": "^2.0.4",
-        "readable-stream": "2 || 3"
-      }
-    },
     "packages/blockly/node_modules/gulp-sourcemaps": {
       "version": "3.0.0",
       "dev": true,
@@ -8935,37 +8921,6 @@
         "any-promise": "^1.1.0"
       }
     },
-    "packages/blockly/node_modules/streamqueue": {
-      "version": "0.0.6",
-      "dev": true,
-      "dependencies": {
-        "readable-stream": "^1.0.26-2"
-      },
-      "engines": {
-        "node": ">= 0.10.0"
-      }
-    },
-    "packages/blockly/node_modules/streamqueue/node_modules/isarray": {
-      "version": "0.0.1",
-      "dev": true,
-      "license": "MIT"
-    },
-    "packages/blockly/node_modules/streamqueue/node_modules/readable-stream": {
-      "version": "1.1.14",
-      "dev": true,
-      "license": "MIT",
-      "dependencies": {
-        "core-util-is": "~1.0.0",
-        "inherits": "~2.0.1",
-        "isarray": "0.0.1",
-        "string_decoder": "~0.10.x"
-      }
-    },
-    "packages/blockly/node_modules/streamqueue/node_modules/string_decoder": {
-      "version": "0.10.31",
-      "dev": true,
-      "license": "MIT"
-    },
     "packages/blockly/node_modules/string_decoder": {
       "version": "1.1.1",
       "dev": true,
@@ -9237,11 +9192,6 @@
         "typescript": ">=4.8.4"
       }
     },
-    "packages/blockly/node_modules/tslib": {
-      "version": "1.14.1",
-      "dev": true,
-      "license": "0BSD"
-    },
     "packages/blockly/node_modules/type": {
       "version": "1.2.0",
       "dev": true,
diff --git a/packages/blockly/core/connection.ts b/packages/blockly/core/connection.ts
index a55c2505915..a79b7b9b143 100644
--- a/packages/blockly/core/connection.ts
+++ b/packages/blockly/core/connection.ts
@@ -291,10 +291,7 @@ export class Connection {
     }
 
     let event;
-    if (
-      eventUtils.isEnabled() &&
-      !childConnection.getSourceBlock().isDeadOrDying()
-    ) {
+    if (eventUtils.isEnabled()) {
       event = new (eventUtils.get(EventType.BLOCK_MOVE))(
         childConnection.getSourceBlock(),
       ) as BlockMove;
diff --git a/packages/blockly/core/css.ts b/packages/blockly/core/css.ts
index de9e682f87e..60ad8604914 100644
--- a/packages/blockly/core/css.ts
+++ b/packages/blockly/core/css.ts
@@ -84,14 +84,7 @@ let content = `
 
 .blocklyBlockCanvas.blocklyCanvasTransitioning,
 .blocklyBubbleCanvas.blocklyCanvasTransitioning {
-  transition: transform .15s;
-}
-
-@media (prefers-reduced-motion) {
-  .blocklyBlockCanvas.blocklyCanvasTransitioning,
-  .blocklyBubbleCanvas.blocklyCanvasTransitioning {
-    transition: none;
-  }
+  transition: transform .5s;
 }
 
 .blocklyEmboss {
@@ -452,17 +445,14 @@ input[type=number] {
 }
 
 /* State: selected/checked. */
-.blocklyMenuItemCheckbox {
-  height: 16px;
-  position: absolute;
-  width: 16px;
-}
-
 .blocklyMenuItemSelected .blocklyMenuItemCheckbox {
   background: url(<<<PATH>>>/sprites.png) no-repeat -48px -16px;
   float: left;
   margin-left: -24px;
+  width: 16px;
+  height: 16px;
   position: static;  /* Scroll with the menu. */
+  display: block;
 }
 
 .blocklyMenuItemRtl .blocklyMenuItemCheckbox {
diff --git a/packages/blockly/core/layer_manager.ts b/packages/blockly/core/layer_manager.ts
index 7d253b11042..1142bcf58d2 100644
--- a/packages/blockly/core/layer_manager.ts
+++ b/packages/blockly/core/layer_manager.ts
@@ -73,11 +73,11 @@ export class LayerManager {
    * @internal
    */
   appendToAnimationLayer(elem: IRenderedElement) {
-    const currentTransform = this.dragLayer?.style.transform;
+    const currentTransform = this.dragLayer?.getAttribute('transform');
     // Only update the current transform when appending, so animations don't
     // move if the workspace moves.
-    if (currentTransform && this.animationLayer) {
-      this.animationLayer.style.transform = currentTransform;
+    if (currentTransform) {
+      this.animationLayer?.setAttribute('transform', currentTransform);
     }
     this.animationLayer?.appendChild(elem.getSvgRoot());
   }
@@ -88,12 +88,10 @@ export class LayerManager {
    * @internal
    */
   translateLayers(newCoord: Coordinate, newScale: number) {
-    const translation = `translate(${newCoord.x}px, ${newCoord.y}px) scale(${newScale})`;
-    if (this.dragLayer) {
-      this.dragLayer.style.transform = translation;
-    }
+    const translation = `translate(${newCoord.x}, ${newCoord.y}) scale(${newScale})`;
+    this.dragLayer?.setAttribute('transform', translation);
     for (const [_, layer] of this.layers) {
-      layer.style.transform = translation;
+      layer.setAttribute('transform', translation);
     }
   }
 
diff --git a/packages/blockly/core/toolbox/toolbox.ts b/packages/blockly/core/toolbox/toolbox.ts
index 6f4daf4ed71..f58536257d3 100644
--- a/packages/blockly/core/toolbox/toolbox.ts
+++ b/packages/blockly/core/toolbox/toolbox.ts
@@ -11,7 +11,6 @@
  */
 // Former goog.module ID: Blockly.Toolbox
 
-// Unused import preserved for side-effects. Remove if unneeded.
 import {BlockSvg} from '../block_svg.js';
 import * as browserEvents from '../browser_events.js';
 import * as common from '../common.js';
@@ -192,7 +191,7 @@ export class Toolbox
     aria.setRole(this.contentsDiv_, aria.Role.TREE);
     container.appendChild(this.contentsDiv_);
 
-    svg.parentNode!.insertBefore(container, svg);
+    svg.parentNode?.insertBefore(container, svg);
 
     this.attachEvents_(container, this.contentsDiv_);
     return container;
@@ -281,7 +280,7 @@ export class Toolbox
       const itemId = (targetElement as Element).getAttribute('id');
       if (itemId) {
         const item = this.getToolboxItemById(itemId);
-        if (item!.isSelectable()) {
+        if (item?.isSelectable()) {
           this.setSelectedItem(item);
           (item as ISelectableToolboxItem).onClick(e);
         }
@@ -396,7 +395,7 @@ export class Toolbox
       const toolboxItemDef = toolboxDef[i];
       this.createToolboxItem(toolboxItemDef, fragment);
     }
-    this.contentsDiv_!.appendChild(fragment);
+    this.contentsDiv_?.appendChild(fragment);
   }
 
   /**
@@ -435,9 +434,7 @@ export class Toolbox
       }
       // Adds the ID to the HTML element that can receive a click.
       // This is used in onClick_ to find the toolboxItem that was clicked.
-      if (toolboxItem.getClickTarget()) {
-        toolboxItem.getClickTarget()!.setAttribute('id', toolboxItem.getId());
-      }
+      toolboxItem.getClickTarget()?.setAttribute('id', toolboxItem.getId());
     }
   }
 
@@ -722,7 +719,7 @@ export class Toolbox
       this.width_ = toolboxDiv.offsetWidth;
       this.height_ = workspaceMetrics.viewHeight;
     }
-    this.flyout!.position();
+    this.flyout?.position();
   }
 
   /**
@@ -731,10 +728,11 @@ export class Toolbox
    * @internal
    */
   handleToolboxItemResize() {
+    if (!this.HtmlDiv) return;
     // Reposition the workspace so that (0,0) is in the correct position
     // relative to the new absolute edge (ie toolbox edge).
     const workspace = this.workspace_;
-    const rect = this.HtmlDiv!.getBoundingClientRect();
+    const rect = this.HtmlDiv.getBoundingClientRect();
     const flyout = this.getFlyout();
     const newX =
       this.toolboxPosition === toolbox.Position.LEFT
@@ -786,7 +784,7 @@ export class Toolbox
       this.selectedItem_.isSelectable() &&
       this.selectedItem_.getContents().length
     ) {
-      this.flyout!.show(this.selectedItem_.getContents());
+      this.flyout?.show(this.selectedItem_.getContents());
     }
   }
 
@@ -800,7 +798,9 @@ export class Toolbox
       return;
     }
 
-    this.HtmlDiv!.style.display = isVisible ? 'block' : 'none';
+    if (this.HtmlDiv) {
+      this.HtmlDiv.style.display = isVisible ? 'block' : 'none';
+    }
     this.isVisible_ = isVisible;
     // Invisible toolbox is ignored as drag targets and must have the drag
     // target updated.
@@ -944,10 +944,10 @@ export class Toolbox
       (oldItem === newItem && !newItem.isCollapsible()) ||
       !newItem.getContents().length
     ) {
-      this.flyout!.hide();
+      this.flyout?.hide();
     } else {
-      this.flyout!.show(newItem.getContents());
-      this.flyout!.scrollToStart();
+      this.flyout?.show(newItem.getContents());
+      this.flyout?.scrollToStart();
     }
   }
 
@@ -992,10 +992,7 @@ export class Toolbox
       const collapsibleItem = this.selectedItem_ as ICollapsibleToolboxItem;
       collapsibleItem.toggleExpanded();
       return true;
-    } else if (
-      this.selectedItem_.getParent() &&
-      this.selectedItem_.getParent()!.isSelectable()
-    ) {
+    } else if (this.selectedItem_.getParent()?.isSelectable()) {
       this.setSelectedItem(this.selectedItem_.getParent());
       return true;
     }
@@ -1075,7 +1072,7 @@ export class Toolbox
   /** Disposes of this toolbox. */
   dispose() {
     this.workspace_.getComponentManager().removeComponent('toolbox');
-    this.flyout!.dispose();
+    this.flyout?.dispose();
     this.contents.forEach((item) => item.dispose());
 
     for (let j = 0; j < this.boundEvents_.length; j++) {
diff --git a/packages/blockly/core/zoom_controls.ts b/packages/blockly/core/zoom_controls.ts
index 6bd1194231b..4f14b73bed6 100644
--- a/packages/blockly/core/zoom_controls.ts
+++ b/packages/blockly/core/zoom_controls.ts
@@ -373,10 +373,8 @@ export class ZoomControls implements IPositionable {
    * @param e A mouse down event.
    */
   private zoom(amount: number, e: PointerEvent) {
-    this.workspace.beginCanvasTransition();
     this.workspace.markFocused();
     this.workspace.zoomCenter(amount);
-    setTimeout(this.workspace.endCanvasTransition.bind(this.workspace), 150);
     this.fireZoomEvent();
     Touch.clearTouchIdentifier(); // Don't block future drags.
     e.stopPropagation(); // Don't start a workspace scroll.
@@ -461,7 +459,7 @@ export class ZoomControls implements IPositionable {
     this.workspace.zoomCenter(amount);
     this.workspace.scrollCenter();
 
-    setTimeout(this.workspace.endCanvasTransition.bind(this.workspace), 150);
+    setTimeout(this.workspace.endCanvasTransition.bind(this.workspace), 500);
     this.fireZoomEvent();
     Touch.clearTouchIdentifier(); // Don't block future drags.
     e.stopPropagation(); // Don't start a workspace scroll.
diff --git a/packages/blockly/gulpfile.mjs b/packages/blockly/gulpfile.mjs
index ad61bcb516d..378d6ce5efa 100644
--- a/packages/blockly/gulpfile.mjs
+++ b/packages/blockly/gulpfile.mjs
@@ -33,18 +33,9 @@ import {
   tsc,
 } from './scripts/gulpfiles/build_tasks.mjs';
 import {docs} from './scripts/gulpfiles/docs_tasks.mjs';
-import {
-  createRC,
-  syncDevelop,
-  syncMaster,
-  updateGithubPages,
-} from './scripts/gulpfiles/git_tasks.mjs';
+import {updateGithubPages} from './scripts/gulpfiles/git_tasks.mjs';
 import {cleanReleaseDir, pack} from './scripts/gulpfiles/package_tasks.mjs';
-import {
-  publish,
-  publishBeta,
-  recompile,
-} from './scripts/gulpfiles/release_tasks.mjs';
+import {publish, publishBeta} from './scripts/gulpfiles/release_tasks.mjs';
 import {
   generators,
   interactiveMocha,
@@ -72,7 +63,7 @@ export {
   prepareDemos,
   deployDemosBeta,
   deployDemos,
-  updateGithubPages as gitUpdateGithubPages,
+  updateGithubPages,
 }
 
 // Manually-invokable targets that also invoke prerequisites where
@@ -86,15 +77,5 @@ export {
   generators as testGenerators,
   interactiveMocha,
   buildAdvancedCompilationTest,
-  createRC as gitCreateRC,
   docs,
 }
-
-// Legacy targets, to be deleted.
-//
-// prettier-ignore
-export {
-  recompile,
-  syncDevelop as gitSyncDevelop,
-  syncMaster as gitSyncMaster,
-}
diff --git a/packages/blockly/package.json b/packages/blockly/package.json
index ad4a58688c6..623e967a312 100644
--- a/packages/blockly/package.json
+++ b/packages/blockly/package.json
@@ -1,16 +1,16 @@
 {
   "name": "blockly",
-  "version": "12.4.1",
+  "version": "12.5.1",
   "description": "Blockly is a library for building visual programming editors.",
   "keywords": [
     "blockly"
   ],
   "repository": {
     "type": "git",
-    "url": "git+https://github.com/google/blockly.git"
+    "url": "git+https://github.com/RaspberryPiFoundation/blockly.git"
   },
   "bugs": {
-    "url": "https://github.com/google/blockly/issues"
+    "url": "https://github.com/RaspberryPiFoundation/blockly/issues"
   },
   "homepage": "https://developers.google.com/blockly/",
   "author": {
@@ -38,8 +38,6 @@
     "prepareDemos": "gulp prepareDemos",
     "publish": "npm ci && gulp publish",
     "publish:beta": "npm ci && gulp publishBeta",
-    "recompile": "gulp recompile",
-    "release": "gulp gitCreateRC",
     "start": "npm run build && concurrently -n tsc,server \"tsc --watch --preserveWatchOutput --outDir \"build/src\" --declarationDir \"build/declarations\"\" \"http-server ./ -s -o /tests/playground.html -c-1\"",
     "tsc": "gulp tsc",
     "test": "gulp test",
@@ -47,7 +45,8 @@
     "test:generators": "gulp testGenerators",
     "test:mocha:interactive": "npm run build && concurrently -n tsc,server \"tsc --watch --preserveWatchOutput --outDir \"build/src\" --declarationDir \"build/declarations\"\" \"gulp interactiveMocha\"",
     "test:compile:advanced": "gulp buildAdvancedCompilationTest --debug",
-    "updateGithubPages": "npm ci && gulp gitUpdateGithubPages"
+    "updateGithubPages": "npm ci && gulp updateGithubPages --upstream",
+    "updateGithubPages:staging": "npm ci && gulp updateGithubPages --use-local"
   },
   "exports": {
     ".": {
@@ -112,6 +111,8 @@
     "async-done": "^2.0.0",
     "chai": "^6.0.1",
     "concurrently": "^9.0.1",
+    "conventional-changelog-conventionalcommits": "^7.0.2",
+    "conventional-recommended-bump": "^9.0.0",
     "eslint": "^9.15.0",
     "eslint-config-google": "^0.14.0",
     "eslint-config-prettier": "^10.1.1",
@@ -125,11 +126,8 @@
     "gulp-concat": "^2.6.1",
     "gulp-gzip": "^1.4.2",
     "gulp-header": "^2.0.9",
-    "gulp-insert": "^0.5.0",
     "gulp-rename": "^2.0.0",
     "gulp-replace": "^1.0.0",
-    "gulp-series": "^1.0.2",
-    "gulp-shell": "^0.8.0",
     "gulp-sourcemaps": "^3.0.0",
     "gulp-umd": "^2.0.0",
     "http-server": "^14.0.0",
diff --git a/packages/blockly/scripts/gulpfiles/git_tasks.mjs b/packages/blockly/scripts/gulpfiles/git_tasks.mjs
index 2b08e16b38b..6a68b54becf 100644
--- a/packages/blockly/scripts/gulpfiles/git_tasks.mjs
+++ b/packages/blockly/scripts/gulpfiles/git_tasks.mjs
@@ -8,17 +8,36 @@
  * @fileoverview Git-related gulp tasks for Blockly.
  */
 
+
 import * as gulp from 'gulp';
 import {execSync} from 'child_process';
+import yargs from 'yargs';
+import { hideBin } from 'yargs/helpers';
 
 import * as buildTasks from './build_tasks.mjs';
 import * as packageTasks from './package_tasks.mjs';
 
-const UPSTREAM_URL = 'https://github.com/google/blockly.git';
+const UPSTREAM_URL = 'git@github.com:RaspberryPiFoundation/blockly.git';
+
+// Use yargs to parse --remote argument
+const argv = yargs(hideBin(process.argv)).option('remote', {
+    type: 'string',
+    describe: 'Remote to push gh-pages to',
+    demandOption: false
+}).option('upstream', {
+  type: 'boolean',
+  describe: 'Push to RaspberryPiFoundation/blockly instead of origin',
+  demandOption: false
+}).option('use-local', {
+  type: 'boolean',
+  describe: 'Build and push from current branch instead of syncing with main',
+  demandOption: false
+}).help().argv;
+const remoteToUse = argv.upstream ? UPSTREAM_URL : resolveRemote(argv.remote);
 
 /**
  * Extra paths to include in the gh_pages branch (beyond the normal
- * contents of master / develop).  Passed to shell unquoted, so can
+ * contents of main).  Passed to shell unquoted, so can
  * include globs.
  */
 const EXTRAS = [
@@ -28,140 +47,122 @@ const EXTRAS = [
   'build/*.loader.mjs',
 ];
 
-let upstream = null;
-
 /**
- * Get name of git remote for upstream (typically 'upstream', but this
- * is just convention and can be changed.)
- */
-function getUpstream() {
-  if (upstream) return upstream;
-  for (const line of String(execSync('git remote -v')).split('\n')) {
-    if (line.includes('google/blockly')) {
-      upstream = line.split('\t')[0];
-      return upstream;
-    }
-  }
-  throw new Error('Unable to determine upstream URL');
-}
-
-/**
- * Stash current state, check out the named branch, and sync with
- * google/blockly.
+ * Stash current state, check out the named branch, and pull
+ * changes from RaspberryPiFoundation/blockly.
  */
 function syncBranch(branchName) {
   return function(done) {
     execSync('git stash save -m "Stash for sync"', { stdio: 'inherit' });
     checkoutBranch(branchName);
     execSync(`git pull ${UPSTREAM_URL} ${branchName}`, { stdio: 'inherit' });
-    execSync(`git push origin ${branchName}`, { stdio: 'inherit' });
     done();
   };
 }
 
 /**
- * Stash current state, check out develop, and sync with
- * google/blockly.
+ * Stash current state, check out main, and sync with
+ * RaspberryPiFoundation/blockly.
  */
-export function syncDevelop() {
-  return syncBranch('develop');
+export function syncMain() {
+  return syncBranch('main');
 };
 
 /**
- * Stash current state, check out master, and sync with
- * google/blockly.
- */
-export function syncMaster() {
-  return syncBranch('master');
-};
-
-/**
- * Helper function: get a name for a rebuild branch. Format:
- * rebuild_mm_dd_yyyy.
- */
-function getRebuildBranchName() {
-  const date = new Date();
-  const mm = date.getMonth() + 1;  // Month, 0-11
-  const dd = date.getDate();  // Day of the month, 1-31
-  const yyyy = date.getFullYear();
-  return `rebuild_${mm}_${dd}_${yyyy}`;
-};
-
-/**
- * Helper function: get a name for a rebuild branch. Format:
- * rebuild_yyyy_mm.
- */
-function getRCBranchName() {
-  const date = new Date();
-  const mm = date.getMonth() + 1;  // Month, 0-11
-  const yyyy = date.getFullYear();
-  return `rc_${yyyy}_${mm}`;
-};
-
-/**
- * If branch does not exist then create the branch.
  * If branch exists switch to branch.
+ * If branch does not exist then create the branch.
  */
 function checkoutBranch(branchName) {
-  execSync(`git switch -c ${branchName}`,
+  execSync(`git switch ${branchName} || git switch -c ${branchName}`,
       { stdio: 'inherit' });
 }
 
 /**
- * Create and push an RC branch.
- * Note that this pushes to google/blockly.
- */
-export const createRC = gulp.series(
-  syncDevelop(),
-  function(done) {
-    const branchName = getRCBranchName();
-    execSync(`git switch -C ${branchName}`, { stdio: 'inherit' });
-    execSync(`git push ${UPSTREAM_URL} ${branchName}`, { stdio: 'inherit' });
-    done();
-  }
-);
-
-/** Create the rebuild branch. */
-export function createRebuildBranch(done) {
-  const branchName = getRebuildBranchName();
-  console.log(`make-rebuild-branch: creating branch ${branchName}`);
-  execSync(`git switch -C ${branchName}`, { stdio: 'inherit' });
-  done();
-}
-
-/** Push the rebuild branch to origin. */
-export function pushRebuildBranch(done) {
-  console.log('push-rebuild-branch: committing rebuild');
-  execSync('git commit -am "Rebuild"', { stdio: 'inherit' });
-  const branchName = getRebuildBranchName();
-  execSync(`git push origin ${branchName}`, { stdio: 'inherit' });
-  console.log(`Branch ${branchName} pushed to GitHub.`);
-  console.log('Next step: create a pull request against develop.');
-  done();
-}
-
-/**
- * Update github pages with what is currently in develop.
+ * Update github pages with what is currently in main (or current branch if --use-local).
  *
  * Prerequisites (invoked): clean, build.
+ *
+ * Usage:
+ *   gulp updateGithubPages # sync main, then use origin if exists
+ *   gulp updateGithubPages --upstream # uses hardcoded upstream
+ *   gulp updateGithubPages --remote <remote> # uses named remote
+ *   gulp updateGithubPages --use-local # build from current branch, skip syncing main
+ *
  */
 export const updateGithubPages = gulp.series(
-  function(done) {
-    execSync('git stash save -m "Stash for sync"', { stdio: 'inherit' });
-    execSync('git switch -C gh-pages', { stdio: 'inherit' });
-    execSync(`git fetch ${getUpstream()}`, { stdio: 'inherit' });
-    execSync(`git reset --hard ${getUpstream()}/develop`, { stdio: 'inherit' });
-    done();
-  },
-  buildTasks.cleanBuildDir,
-  packageTasks.cleanReleaseDir,
-  buildTasks.build,
-  function(done) {
-    // Extra paths (e.g. build/, dist/ etc.) are normally gitignored,
-    // so we have to force add.
-    execSync(`git add -f ${EXTRAS.join(' ')}`, {stdio: 'inherit'});
-    execSync('git commit -am "Rebuild"', {stdio: 'inherit'});
-    execSync(`git push ${UPSTREAM_URL} gh-pages --force`, {stdio: 'inherit'});
-    done();
+    function (done) {
+        if (!remoteToUse) {
+          const attemptedRemote = argv.remote || 'origin';
+          const remoteLabel = argv.remote
+            ? `Remote '${attemptedRemote}'`
+            : "Remote 'origin' (default)";
+          const errMsg = `${remoteLabel} not found in git remotes. ` +
+            'Please add that remote or use --upstream.\n' +
+            'Usage: gulp updateGithubPages [--remote <remote> | --upstream]';
+          console.error(errMsg);
+          done(new Error(errMsg));
+          return;
+        }
+        done();
+    },
+    function (done) {
+      if (!argv.useLocal) {
+        done();
+        return;
+      }
+      const status = execSync('git status --porcelain', { encoding: 'utf8' });
+      if (status.trim()) {
+        const errMsg =
+          'You cannot push the local branch with uncommitted changes. ' +
+          'Please commit or stash your changes first.';
+        console.error(errMsg);
+        done(new Error(errMsg));
+        return;
+      }
+      done();
+    },
+    function (done) {
+      if (argv.useLocal) {
+        done();
+        return;
+      }
+      syncMain()(done);
+    },
+    function(done) {
+      const sourceRef = argv.useLocal
+        ? execSync('git rev-parse HEAD', { encoding: 'utf8' }).trim()
+        : 'main';
+      execSync('git switch -C gh-pages', { stdio: 'inherit' });
+      execSync(`git reset --hard ${sourceRef}`, { stdio: 'inherit' });
+      done();
+    },
+    buildTasks.cleanBuildDir,
+    packageTasks.cleanReleaseDir,
+    buildTasks.build,
+    function(done) {
+      // Extra paths (e.g. build/, dist/ etc.) are normally gitignored,
+      // so we have to force add.
+      execSync(`git add -f ${EXTRAS.join(' ')}`, {stdio: 'inherit'});
+      execSync('git commit -am "Rebuild"', {stdio: 'inherit'});
+      execSync(`git push ${remoteToUse} gh-pages --force`, {stdio: 'inherit'});
+      done();
+    }
+  );
+
+/**
+ * Resolves which remote to use for pushing gh-pages.
+ * @param {string} remoteArg
+ * @returns {string|undefined} The remote name, or undefined if not found.
+ */
+function resolveRemote(remoteArg) {
+  const remoteName = remoteArg || 'origin';
+  try {
+    const remotes = execSync('git remote', {encoding: 'utf8'}).split(/\r?\n/).map(r => r.trim()).filter(Boolean);
+    if (remotes.includes(remoteName)) {
+      return remoteName;
+    }
+    return undefined;
+  } catch (e) {
+    return undefined;
   }
-);
+}
diff --git a/packages/blockly/scripts/gulpfiles/release_tasks.mjs b/packages/blockly/scripts/gulpfiles/release_tasks.mjs
index a678a4f2436..ca9c9ffa1bc 100644
--- a/packages/blockly/scripts/gulpfiles/release_tasks.mjs
+++ b/packages/blockly/scripts/gulpfiles/release_tasks.mjs
@@ -18,55 +18,6 @@ import * as packageTasks from './package_tasks.mjs';
 import {getPackageJson} from './helper_tasks.mjs';
 import {RELEASE_DIR} from './config.mjs';
 
-
-// Gets the current major version.
-function getMajorVersion() {
-  const { version } = getPackageJson();
-  const re = new RegExp(/^(\d)./);
-  const match = re.exec(version);
-  if (!match[0]) {
-    return null;
-  }
-  console.log(match[0]);
-  return parseInt(match[0]);
-}
-
-// Updates the version depending on user input.
-function updateVersion(done, updateType) {
-  const majorVersion = getMajorVersion();
-  if (!majorVersion) {
-    done(new Error('Something went wrong when getting the major version number.'));
-  } else if (!updateType) {
-    // User selected to cancel.
-    done(new Error('Cancelling process.'));
-  }
-
-  switch (updateType.toLowerCase()) {
-    case 'major':
-      majorVersion++;
-      execSync(`npm --no-git-tag-version version ${majorVersion}.$(date +'%Y%m%d').0`, {stdio: 'inherit'});
-      done();
-      break;
-    case 'minor':
-      execSync(`npm --no-git-tag-version version ${majorVersion}.$(date +'%Y%m%d').0`, {stdio: 'inherit'});
-      done();
-      break;
-    case 'patch':
-      execSync(`npm --no-git-tag-version version patch`, {stdio: 'inherit'});
-      done();
-      break;
-    default:
-      done(new Error('Unexpected update type was chosen.'))
-  }
-}
-
-// Prompt the user to figure out what kind of version update we should do.
-function updateVersionPrompt(done) {
-  const releaseTypes = ['Major', 'Minor', 'Patch'];
-  const index = readlineSync.keyInSelect(releaseTypes, 'Which version type?');
-  updateVersion(done, releaseTypes[index]);
-}
-
 // Checks with the user that they are on the correct git branch.
 function checkBranch(done) {
   const gitBranchName = execSync('git rev-parse --abbrev-ref HEAD').toString();
@@ -162,13 +113,3 @@ export const publishBeta = gulp.series(
   checkReleaseDir,
   loginAndPublishBeta
 );
-
-// Switch to a new branch, update the version number, build Blockly
-// and check in the resulting built files.
-export const recompile = gulp.series(
-  gitTasks.syncDevelop(),
-  gitTasks.createRebuildBranch,
-  updateVersionPrompt,
-  packageTasks.pack,  // Does clean + build.
-  gitTasks.pushRebuildBranch
-  );