1 files changed, 37 insertions, 9 deletions
diff --git a/doc/user/project/merge_requests/code_quality.md b/doc/user/project/merge_requests/code_quality.md
index 42c2547a618..0fe1b9801cc 100644
--- a/doc/user/project/merge_requests/code_quality.md
+++ b/doc/user/project/merge_requests/code_quality.md
@@ -15,7 +15,7 @@ source code quality using GitLab Code Quality.
 
 Code Quality:
 
-- Uses [Code Climate Engines](https://codeclimate.com), which are
+- Uses [Engines](https://docs.codeclimate.com/docs/list-of-engines) supported by Code Climate, which are
   free and open source. Code Quality does not require a Code Climate
   subscription.
 - Runs in [pipelines](../../../ci/pipelines/index.md) using a Docker image built in the
@@ -33,7 +33,7 @@ Code Quality:
 Going a step further, GitLab can show the Code Quality report right
 in the merge request widget area if a report from the target branch is available to compare to:
 
-![Code Quality Widget](img/code_quality.png)
+![Code Quality Widget](img/code_quality_widget_13_11.png)
 
 Watch a quick walkthrough of Code Quality in action:
 
@@ -49,6 +49,26 @@ For one customer, the auditor found that having Code Quality, SAST, and Containe
 
 See also the Code Climate list of [Supported Languages for Maintainability](https://docs.codeclimate.com/docs/supported-languages-for-maintainability).
 
+## Code Quality in diff view **(ULTIMATE)**
+
+> - [Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/267612) in [GitLab Ultimate](https://about.gitlab.com/pricing/) 13.11.
+> - [Deployed behind a feature flag](../../../user/feature_flags.md), disabled by default.
+
+Changes to files in merge requests can cause Code Quality to fall if merged. In these cases,
+an indicator is displayed (**{information-o}** **Code Quality**) on the file in the merge request's diff view. For example:
+
+![Code Quality MR diff report](img/code_quality_mr_diff_report_v13_11.png)
+
+To enable this feature, a GitLab administrator can run the following in a
+[Rails console](../../../administration/operations/rails_console.md):
+
+```ruby
+# For the instance
+Feature.enable(:codequality_mr_diff)
+# For a single project
+Feature.enable(:codequality_mr_diff, Project.find(<project id>))
+```
+
 ## Use cases
 
 For instance, consider the following workflow:
@@ -85,7 +105,7 @@ include:
 
 The above example creates a `code_quality` job in your CI/CD pipeline which
 scans your source code for code quality issues. The report is saved as a
-[Code Quality report artifact](../../../ci/pipelines/job_artifacts.md#artifactsreportscodequality)
+[Code Quality report artifact](../../../ci/yaml/README.md#artifactsreportscodequality)
 that you can later download and analyze.
 
 It's also possible to override the URL to the Code Quality image by
@@ -242,12 +262,11 @@ to learn more about how to define one.
 To disable the `code_quality` job, add `CODE_QUALITY_DISABLED` as a custom CI/CD variable.
 This can be done:
 
-- For the whole project, [in the project settings](../../../ci/variables/README.md#create-a-custom-variable-in-the-ui)
-  or [CI/CD configuration](../../../ci/variables/README.md#create-a-custom-variable-in-the-ui).
+- For [the whole project](../../../ci/variables/README.md#custom-cicd-variables).
 - For a single pipeline run:
 
   1. Go to **CI/CD > Pipelines**
-  1. Click **Run Pipeline**
+  1. Click **Run pipeline**
   1. Add `CODE_QUALITY_DISABLED` as the variable key, with any value.
 
 ### Using with merge request pipelines
@@ -309,7 +328,7 @@ do this:
 
 1. Define a job in your `.gitlab-ci.yml` file that generates the
    [Code Quality report
-   artifact](../../../ci/pipelines/job_artifacts.md#artifactsreportscodequality).
+   artifact](../../../ci/yaml/README.md#artifactsreportscodequality).
 1. Configure your tool to generate the Code Quality report artifact as a JSON
    file that implements a subset of the [Code Climate
    spec](https://github.com/codeclimate/platform/blob/master/spec/analyzers/SPEC.md#data-types).
@@ -347,7 +366,11 @@ NOTE:
 Although the Code Climate spec supports more properties, those are ignored by
 GitLab.
 
-## Code Quality reports
+## Code Quality reports **(PREMIUM)**
+
+> [Introduced](https://gitlab.com/gitlab-org/gitlab/-/merge_requests/21527) in GitLab Premium 12.9.
+
+![Code Quality Report](img/code_quality_report_13_11.png)
 
 After the Code Quality job completes:
 
@@ -355,7 +378,7 @@ After the Code Quality job completes:
   The Code Quality widget in the merge request compares the reports from the base and head of the branch,
   then lists any violations that are resolved or created when the branch is merged.
 - The full JSON report is available as a
-  [downloadable artifact](../../../ci/pipelines/job_artifacts.md#downloading-artifacts)
+  [downloadable artifact](../../../ci/pipelines/job_artifacts.md#download-job-artifacts)
   for the `code_quality` job.
 - The full list of code quality violations generated by a pipeline is shown in the
   Code Quality tab of the Pipeline Details page. **(PREMIUM)**
@@ -552,3 +575,8 @@ plugins:
     enabled: true
     channel: rubocop-0-67
 ```
+
+### No Code Quality appears on merge requests when using custom tool
+
+If your merge requests do not show any code quality changes when using a custom tool,
+ensure that the line property is an `integer`.