diff --git a/src/doc/rustc-dev-guide/.github/workflows/ci.yml b/src/doc/rustc-dev-guide/.github/workflows/ci.yml
index 006bcce44b3d5..3f810e2fbcc99 100644
--- a/src/doc/rustc-dev-guide/.github/workflows/ci.yml
+++ b/src/doc/rustc-dev-guide/.github/workflows/ci.yml
@@ -41,7 +41,9 @@ jobs:
         uses: actions/cache/restore@v4
         with:
           path: book/linkcheck/cache.json
-          key: linkcheck--${{ env.MDBOOK_LINKCHECK2_VERSION }}
+          key: linkcheck--${{ env.MDBOOK_LINKCHECK2_VERSION }}--${{ github.run_id }}
+          restore-keys: |
+            linkcheck--${{ env.MDBOOK_LINKCHECK2_VERSION }}--
 
       - name: Install latest nightly Rust toolchain
         if: steps.mdbook-cache.outputs.cache-hit != 'true'
@@ -66,7 +68,7 @@ jobs:
         uses: actions/cache/save@v4
         with:
           path: book/linkcheck/cache.json
-          key: linkcheck--${{ env.MDBOOK_LINKCHECK2_VERSION }}
+          key: linkcheck--${{ env.MDBOOK_LINKCHECK2_VERSION }}--${{ github.run_id }}
 
       - name: Deploy to gh-pages
         if: github.event_name == 'push'
diff --git a/src/doc/rustc-dev-guide/.github/workflows/rustc-pull.yml b/src/doc/rustc-dev-guide/.github/workflows/rustc-pull.yml
index 87a3ee2e78f1d..615927d55e597 100644
--- a/src/doc/rustc-dev-guide/.github/workflows/rustc-pull.yml
+++ b/src/doc/rustc-dev-guide/.github/workflows/rustc-pull.yml
@@ -50,10 +50,10 @@ jobs:
           RESULT=`gh pr list --author github-actions[bot] --state open -q 'map(select(.title=="Rustc pull update")) | length' --json title`
           if [[ "$RESULT" -eq 0 ]]; then
             echo "Creating new pull request"
-            PR_URL=gh pr create -B master --title 'Rustc pull update' --body 'Latest update from rustc.'
+            PR_URL=`gh pr create -B master --title 'Rustc pull update' --body 'Latest update from rustc.'`
             echo "pr_url=$PR_URL" >> $GITHUB_OUTPUT
           else
-            PR_URL=gh pr list --author github-actions[bot] --state open -q 'map(select(.title=="Rustc pull update")) | .[0].url' --json url,title
+            PR_URL=`gh pr list --author github-actions[bot] --state open -q 'map(select(.title=="Rustc pull update")) | .[0].url' --json url,title`
             echo "pr_url=$PR_URL" >> $GITHUB_OUTPUT
           fi
         env:
diff --git a/src/doc/rustc-dev-guide/rust-version b/src/doc/rustc-dev-guide/rust-version
index 9693bfd63e84d..183d26b293842 100644
--- a/src/doc/rustc-dev-guide/rust-version
+++ b/src/doc/rustc-dev-guide/rust-version
@@ -1 +1 @@
-ecda83b30f0f68cf5692855dddc0bc38ee8863fc
+66d6064f9eb888018775e08f84747ee6f39ba28e
diff --git a/src/doc/rustc-dev-guide/src/about-this-guide.md b/src/doc/rustc-dev-guide/src/about-this-guide.md
index 793bfa9e66e59..781a5c51bf7a8 100644
--- a/src/doc/rustc-dev-guide/src/about-this-guide.md
+++ b/src/doc/rustc-dev-guide/src/about-this-guide.md
@@ -72,7 +72,6 @@ You might also find the following sites useful:
 - The [Rust reference][rr], even though it doesn't specifically talk about
   Rust's internals, is a great resource nonetheless
 - Although out of date, [Tom Lee's great blog article][tlgba] is very helpful
-- [rustaceans.org][ro] is helpful, but mostly dedicated to IRC
 - The [Rust Compiler Testing Docs][rctd]
 - For [@bors], [this cheat sheet][cheatsheet] is helpful
 - Google is always helpful when programming.
diff --git a/src/doc/rustc-dev-guide/src/backend/libs-and-metadata.md b/src/doc/rustc-dev-guide/src/backend/libs-and-metadata.md
index b0823b9a5eed3..556b3fdf8f84f 100644
--- a/src/doc/rustc-dev-guide/src/backend/libs-and-metadata.md
+++ b/src/doc/rustc-dev-guide/src/backend/libs-and-metadata.md
@@ -42,7 +42,7 @@ format is specific to `rustc`, and may change over time. This file contains:
 ### dylib
 
 A `dylib` is a platform-specific shared library. It includes the `rustc`
-[metadata] in a special link section called `.rustc` in a compressed format.
+[metadata] in a special link section called `.rustc`.
 
 ### rmeta
 
diff --git a/src/doc/rustc-dev-guide/src/diagnostics.md b/src/doc/rustc-dev-guide/src/diagnostics.md
index 709e9d4f88935..8f389640d271f 100644
--- a/src/doc/rustc-dev-guide/src/diagnostics.md
+++ b/src/doc/rustc-dev-guide/src/diagnostics.md
@@ -602,7 +602,7 @@ as the linter walks the AST. You can then choose to emit lints in a
 very similar way to compile errors.
 
 You also declare the metadata of a particular lint via the `declare_lint!`
-macro. This includes the name, the default level, a short description, and some
+macro. [This macro](https://doc.rust-lang.org/nightly/nightly-rustc/rustc_lint_defs/macro.declare_lint.html) includes the name, the default level, a short description, and some
 more details.
 
 Note that the lint and the lint pass must be registered with the compiler.
diff --git a/src/doc/rustc-dev-guide/src/early_late_parameters.md b/src/doc/rustc-dev-guide/src/early_late_parameters.md
index 6d13655294d3e..3b2a5e8a155b6 100644
--- a/src/doc/rustc-dev-guide/src/early_late_parameters.md
+++ b/src/doc/rustc-dev-guide/src/early_late_parameters.md
@@ -126,9 +126,9 @@ In this example we call `foo`'s function item type twice, each time with a borro
 If the lifetime parameter on `foo` was late bound this would be able to compile as each caller could provide a different lifetime argument for its borrow. See the following example which demonstrates this using the `bar` function defined above:
 
 ```rust
-#fn foo<'a: 'a>(b: &'a String) -> &'a String { b }
-#fn bar<'a>(b: &'a String) -> &'a String { b }
-
+# fn foo<'a: 'a>(b: &'a String) -> &'a String { b }
+# fn bar<'a>(b: &'a String) -> &'a String { b }
+#
 // Early bound parameters are instantiated here, however as `'a` is
 // late bound it is not provided here.
 let b = bar;
@@ -220,24 +220,24 @@ Then, for the first case, we can call each function with a single lifetime argum
 ```rust
 #![deny(late_bound_lifetime_arguments)]
 
-#fn free_function<'a: 'a, 'b>(_: &'a (), _: &'b ()) {}
+# fn free_function<'a: 'a, 'b>(_: &'a (), _: &'b ()) {}
 #
-#struct Foo;
+# struct Foo;
 #
-#trait Trait: Sized {
-#    fn trait_method<'a: 'a, 'b>(self, _: &'a (), _: &'b ());
-#    fn trait_function<'a: 'a, 'b>(_: &'a (), _: &'b ());
-#}
+# trait Trait: Sized {
+#     fn trait_method<'a: 'a, 'b>(self, _: &'a (), _: &'b ());
+#     fn trait_function<'a: 'a, 'b>(_: &'a (), _: &'b ());
+# }
 #
-#impl Trait for Foo {
-#    fn trait_method<'a: 'a, 'b>(self, _: &'a (), _: &'b ()) {}
-#    fn trait_function<'a: 'a, 'b>(_: &'a (), _: &'b ()) {}
-#}
+# impl Trait for Foo {
+#     fn trait_method<'a: 'a, 'b>(self, _: &'a (), _: &'b ()) {}
+#     fn trait_function<'a: 'a, 'b>(_: &'a (), _: &'b ()) {}
+# }
 #
-#impl Foo {
-#    fn inherent_method<'a: 'a, 'b>(self, _: &'a (), _: &'b ()) {}
-#    fn inherent_function<'a: 'a, 'b>(_: &'a (), _: &'b ()) {}
-#}
+# impl Foo {
+#     fn inherent_method<'a: 'a, 'b>(self, _: &'a (), _: &'b ()) {}
+#     fn inherent_function<'a: 'a, 'b>(_: &'a (), _: &'b ()) {}
+# }
 #
 // Specifying as many arguments as there are early
 // bound parameters is always a future compat warning
@@ -251,24 +251,24 @@ free_function::<'static>(&(), &());
 
 For the second case we call each function with more lifetime arguments than there are lifetime parameters (be it early or late bound) and note that method calls result in a FCW as opposed to the free/associated functions which result in a hard error:
 ```rust
-#fn free_function<'a: 'a, 'b>(_: &'a (), _: &'b ()) {}
+# fn free_function<'a: 'a, 'b>(_: &'a (), _: &'b ()) {}
 #
-#struct Foo;
+# struct Foo;
 #
-#trait Trait: Sized {
-#    fn trait_method<'a: 'a, 'b>(self, _: &'a (), _: &'b ());
-#    fn trait_function<'a: 'a, 'b>(_: &'a (), _: &'b ());
-#}
+# trait Trait: Sized {
+#     fn trait_method<'a: 'a, 'b>(self, _: &'a (), _: &'b ());
+#     fn trait_function<'a: 'a, 'b>(_: &'a (), _: &'b ());
+# }
 #
-#impl Trait for Foo {
-#    fn trait_method<'a: 'a, 'b>(self, _: &'a (), _: &'b ()) {}
-#    fn trait_function<'a: 'a, 'b>(_: &'a (), _: &'b ()) {}
-#}
+# impl Trait for Foo {
+#     fn trait_method<'a: 'a, 'b>(self, _: &'a (), _: &'b ()) {}
+#     fn trait_function<'a: 'a, 'b>(_: &'a (), _: &'b ()) {}
+# }
 #
-#impl Foo {
-#    fn inherent_method<'a: 'a, 'b>(self, _: &'a (), _: &'b ()) {}
-#    fn inherent_function<'a: 'a, 'b>(_: &'a (), _: &'b ()) {}
-#}
+# impl Foo {
+#     fn inherent_method<'a: 'a, 'b>(self, _: &'a (), _: &'b ()) {}
+#     fn inherent_function<'a: 'a, 'b>(_: &'a (), _: &'b ()) {}
+# }
 #
 // Specifying more arguments than there are early
 // bound parameters is a future compat warning when
@@ -421,4 +421,4 @@ impl<'a> Fn<()> for FooFnItem<'a> {
     type Output = &'a String;
     /* fn call(...) -> ... { ... } */
 }
-```
\ No newline at end of file
+```
diff --git a/src/doc/rustc-dev-guide/src/getting-started.md b/src/doc/rustc-dev-guide/src/getting-started.md
index 03d2811e8b108..4cb1d0b31ebd2 100644
--- a/src/doc/rustc-dev-guide/src/getting-started.md
+++ b/src/doc/rustc-dev-guide/src/getting-started.md
@@ -137,6 +137,10 @@ pull request, continuing the work on the feature.
 
 [abandoned-prs]: https://github.com/rust-lang/rust/pulls?q=is%3Apr+label%3AS-inactive+is%3Aclosed
 
+### Writing tests
+
+Issues that have been resolved but do not have a regression test are marked with the `E-needs-test` label. Writing unit tests is a low-risk, lower-priority task that offers new contributors a great opportunity to familiarize themselves with the testing infrastructure and contribution workflow.
+
 ### Contributing to std (standard library)
 
 See [std-dev-guide](https://std-dev-guide.rust-lang.org/).
diff --git a/src/doc/rustc-dev-guide/src/rustdoc.md b/src/doc/rustc-dev-guide/src/rustdoc.md
index 3867d2489886d..2a0e212f98e31 100644
--- a/src/doc/rustc-dev-guide/src/rustdoc.md
+++ b/src/doc/rustc-dev-guide/src/rustdoc.md
@@ -58,10 +58,13 @@ does is call the `main()` that's in this crate's `lib.rs`, though.)
   * If you want to copy those docs to a webserver, copy all of
     `build/host/doc`, since that's where the CSS, JS, fonts, and landing
     page are.
+  * For frontend debugging, disable the `rust.docs-minification` option in [`config.toml`].
 * Use `./x test tests/rustdoc*` to run the tests using a stage1
   rustdoc.
   * See [Rustdoc internals] for more information about tests.
 
+[`config.toml`]: ./building/how-to-build-and-run.md
+
 ## Code structure
 
 * All paths in this section are relative to `src/librustdoc` in the rust-lang/rust repository.
@@ -77,6 +80,7 @@ does is call the `main()` that's in this crate's `lib.rs`, though.)
 * The tests on the structure of rustdoc HTML output are located in `tests/rustdoc`, where
   they're handled by the test runner of bootstrap and the supplementary script
   `src/etc/htmldocck.py`.
+* Frontend CSS and JavaScript are stored in `html/static/`.
 
 ## Tests
 
@@ -91,6 +95,11 @@ does is call the `main()` that's in this crate's `lib.rs`, though.)
   browser-UI-test](https://github.com/GuillaumeGomez/browser-UI-test/) that uses
   puppeteer to run tests in a headless browser and check rendering and
   interactivity.
+* Additionally, JavaScript type annotations are written using [TypeScript-flavored JSDoc]
+  comments and an external d.ts file. The code itself is plain, valid JavaScript; we only
+  use tsc as a linter.
+
+[TypeScript-flavored JSDoc]: https://www.typescriptlang.org/docs/handbook/jsdoc-supported-types.html
 
 ## Constraints
 
diff --git a/src/doc/rustc-dev-guide/src/solve/significant-changes.md b/src/doc/rustc-dev-guide/src/solve/significant-changes.md
index c5bb8a01b12b5..c82b5d468961a 100644
--- a/src/doc/rustc-dev-guide/src/solve/significant-changes.md
+++ b/src/doc/rustc-dev-guide/src/solve/significant-changes.md
@@ -42,7 +42,7 @@ old implementation structurally relates the aliases instead. This enables the
 new solver to stall equality until it is able to normalize the related aliases.
 
 The behavior of the old solver is incomplete and relies on eager normalization
-which replaces ambiguous aliases with inference variables. As this is not
+which replaces ambiguous aliases with inference variables. As this is
 not possible for aliases containing bound variables, the old implementation does
 not handle aliases inside of binders correctly, e.g. [#102048]. See the chapter on
 [normalization] for more details.