diff --git a/.github/workflows/clippy-fmt.yml b/.github/workflows/clippy-fmt.yml
index 9fcb0a561..bc2cec145 100644
--- a/.github/workflows/clippy-fmt.yml
+++ b/.github/workflows/clippy-fmt.yml
@@ -46,3 +46,21 @@ jobs:
         with:
           token: ${{ secrets.GITHUB_TOKEN }}
           args: --workspace --tests --examples --all-features
+
+  lint-docs:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - name: Install Rust
+        uses: actions-rs/toolchain@v1
+        with:
+          toolchain: stable
+          profile: minimal
+          components: rust-docs
+      - name: Check for broken intra-doc links
+        uses: actions-rs/cargo@v1
+        env:
+          RUSTDOCFLAGS: "-D warnings"
+        with:
+          command: doc
+          args: --no-deps --all-features --workspace
diff --git a/actix-files/src/named.rs b/actix-files/src/named.rs
index 14495e660..baf9b5531 100644
--- a/actix-files/src/named.rs
+++ b/actix-files/src/named.rs
@@ -209,6 +209,7 @@ impl NamedFile {
         Self::from_file(file, path)
     }
 
+    #[allow(rustdoc::broken_intra_doc_links)]
     /// Attempts to open a file asynchronously in read-only mode.
     ///
     /// When the `experimental-io-uring` crate feature is enabled, this will be async.
@@ -298,9 +299,11 @@ impl NamedFile {
         self
     }
 
-    /// Set content encoding for serving this file
+    /// Sets content encoding for this file.
     ///
-    /// Must be used with [`actix_web::middleware::Compress`] to take effect.
+    /// This prevents the `Compress` middleware from modifying the file contents and signals to
+    /// browsers/clients how to decode it. For example, if serving a compressed HTML file (e.g.,
+    /// `index.html.gz`) then use `.set_content_encoding(ContentEncoding::Gzip)`.
     #[inline]
     pub fn set_content_encoding(mut self, enc: ContentEncoding) -> Self {
         self.encoding = Some(enc);
diff --git a/src/app.rs b/src/app.rs
index c6582766a..a63cf5d50 100644
--- a/src/app.rs
+++ b/src/app.rs
@@ -236,12 +236,14 @@ where
         self
     }
 
-    /// Default service to be used if no matching resource could be found.
+    /// Default service that is invoked when no matching resource could be found.
     ///
-    /// It is possible to use services like `Route` and [`NamedFile`].
+    /// You can use a [`Route`] as default service.
     ///
-    /// [`NamedFile`]: https://docs.rs/actix-files/latest/actix_files/struct.NamedFile.html
+    /// If a default service is not registered, an empty `404 Not Found` response will be sent to
+    /// the client instead.
     ///
+    /// # Examples
     /// ```
     /// use actix_web::{web, App, HttpResponse};
     ///
@@ -250,23 +252,8 @@ where
     /// }
     ///
     /// let app = App::new()
-    ///     .service(
-    ///         web::resource("/index.html").route(web::get().to(index)))
-    ///     .default_service(
-    ///         web::route().to(|| HttpResponse::NotFound()));
-    /// ```
-    ///
-    /// It is also possible to use static files as default service.
-    ///
-    /// ```
-    /// use actix_web::{web, App, HttpResponse};
-    ///
-    /// let app = App::new()
-    ///     .service(
-    ///         web::resource("/index.html").to(|| HttpResponse::Ok()))
-    ///     .default_service(
-    ///         web::to(|| HttpResponse::NotFound())
-    ///     );
+    ///     .service(web::resource("/index.html").route(web::get().to(index)))
+    ///     .default_service(web::to(|| HttpResponse::NotFound()));
     /// ```
     pub fn default_service<F, U>(mut self, svc: F) -> Self
     where
diff --git a/src/app_service.rs b/src/app_service.rs
index edfb3e4a2..dbd718330 100644
--- a/src/app_service.rs
+++ b/src/app_service.rs
@@ -72,7 +72,7 @@ where
             })))
         });
 
-        // App config
+        // create App config to pass to child services
         let mut config = AppService::new(config, default.clone());
 
         // register services
diff --git a/src/resource.rs b/src/resource.rs
index a0fc19faf..6a01a0496 100644
--- a/src/resource.rs
+++ b/src/resource.rs
@@ -313,8 +313,12 @@ where
     }
 
     /// Default service to be used if no matching route could be found.
-    /// By default *405* response get returned. Resource does not use
-    /// default handler from `App` or `Scope`.
+    ///
+    /// You can use a [`Route`] as default service.
+    ///
+    /// If a default service is not registered, an empty `405 Method Not Allowed` response will be
+    /// sent to the client instead. Unlike [`Scope`](crate::Scope)s, a [`Resource`] does **not**
+    /// inherit its parent's default service.
     pub fn default_service<F, U>(mut self, f: F) -> Self
     where
         F: IntoServiceFactory<U, ServiceRequest>,
diff --git a/src/scope.rs b/src/scope.rs
index c05ce054d..dad727430 100644
--- a/src/scope.rs
+++ b/src/scope.rs
@@ -262,9 +262,10 @@ where
         )
     }
 
-    /// Default service to be used if no matching route could be found.
+    /// Default service to be used if no matching resource could be found.
     ///
-    /// If default resource is not registered, app's default resource is being used.
+    /// If a default service is not registered, it will fall back to the default service of
+    /// the parent [`App`](crate::App) (see [`App::default_service`](crate::App::default_service)).
     pub fn default_service<F, U>(mut self, f: F) -> Self
     where
         F: IntoServiceFactory<U, ServiceRequest>,