The rustc book appears to be out of date

[str4d]

Location

https://doc.rust-lang.org/rustc/linker-plugin-lto.html

Summary

The above URL does not show the content currently in the rustc book source: https://github.com/rust-lang/rust/blob/master/src/doc/rustc/src/linker-plugin-lto.md

Specifically, the rendered docs only show the LTO table up to Rust 1.60, whereas the source includes up to 1.65 after #103955 was merged in #104138.

[Mark-Simulacrum]

https://doc.rust-lang.org/nightly/rustc/linker-plugin-lto.html is the nightly page; the one you linked is only updated on a new stable release. In this case #104138 merged into 1.67 and so will ship January 26th.