diff --git a/nix/packages/extension-catalog.nix b/nix/packages/extension-catalog.nix
index d8d559121..547f7baaa 100644
--- a/nix/packages/extension-catalog.nix
+++ b/nix/packages/extension-catalog.nix
@@ -116,13 +116,6 @@
           ''
         )
       ) perMajor;
-
-      versions = lib.mapAttrs' (
-        major: wrappers:
-        lib.nameValuePair "site-extensions-versions-${major}" (
-          lib.recurseIntoAttrs (lib.mapAttrs (_: lib.recurseIntoAttrs) wrappers)
-        )
-      ) perMajor;
     in
     {
       packages = catalogs // {
@@ -163,6 +156,6 @@
           '';
         };
       };
-      legacyPackages = catalogs // versions;
+      legacyPackages = catalogs;
     };
 }
diff --git a/nix/packages/postgres.nix b/nix/packages/postgres.nix
index 87daccdae..2568cc109 100644
--- a/nix/packages/postgres.nix
+++ b/nix/packages/postgres.nix
@@ -142,6 +142,22 @@
         in
         map (path: extCallPackage path { }) extensionsToUse;
 
+      # Build a single extension package, standalone (not the whole server's set).
+      makeSingleExt =
+        version: latestOnly: extPath:
+        let
+          postgresql = getPostgresqlPackage version latestOnly;
+          extCallPackage = pkgs.lib.callPackageWith (
+            pkgs
+            // {
+              inherit postgresql latestOnly;
+              switch-ext-version = extCallPackage ./switch-ext-version.nix { };
+              overlayfs-on-package = extCallPackage ./overlayfs-on-package.nix { };
+            }
+          );
+        in
+        extCallPackage extPath { };
+
       # Create an attrset that contains all the extensions included in a server.
       makeOurPostgresPkgsSet =
         version:
@@ -215,18 +231,30 @@
       #  - bin: the postgresql package itself, with all the extensions
       #    installed, and a receipt.json file containing metadata about the
       #    install.
-      #  - exts: an attrset containing all the extensions, mapped to their
-      #    package names.
+      #  - exts: an attrset containing extension packages. The "cli" variant
+      #    doesn't expose it (nothing reads it: checks.nix's cli check
+      #    harness borrows pgroonga from the full psql_17 instead). The
+      #    "slim" variants (latestOnly) only expose pgroonga, the one
+      #    extension checks.nix actually needs from them, instead of every
+      #    extension - each of which would otherwise be its own CI job.
       makePostgres =
         version:
         {
           variant ? "full",
           latestOnly ? false,
         }:
-        lib.recurseIntoAttrs {
-          bin = makePostgresBin version { inherit variant latestOnly; };
-          exts = makeOurPostgresPkgsSet version { inherit variant latestOnly; };
-        };
+        lib.recurseIntoAttrs (
+          {
+            bin = makePostgresBin version { inherit variant latestOnly; };
+          }
+          // lib.optionalAttrs (variant != "cli") {
+            exts =
+              if latestOnly then
+                { pgroonga = makeSingleExt version latestOnly ../ext/pgroonga; }
+              else
+                makeOurPostgresPkgsSet version { inherit variant latestOnly; };
+          }
+        );
       basePackages = {
         psql_15 = makePostgres "15" { };
         psql_17 = makePostgres "17" { };