[Feb 15, 2022] Document CODEOWNERS errors (github#24861)

content/repositories/managing-your-repositorys-settings-and-features/customizing-your-repository/about-code-owners.md

@@ -49,9 +49,14 @@ To reduce the size of your CODEOWNERS file, consider using wildcard patterns to
 
 A CODEOWNERS file uses a pattern that follows most of the same rules used in [gitignore](https://git-scm.com/docs/gitignore#_pattern_format) files, with [some exceptions](#syntax-exceptions). The pattern is followed by one or more {% data variables.product.prodname_dotcom %} usernames or team names using the standard `@username` or `@org/team-name` format. Users must have `read` access to the repository and teams must have explicit `write` access, even if the team's members already have access. You can also refer to a user by an email address that has been added to their account on {% ifversion ghae %}{% data variables.product.product_name %}{% else %}{% data variables.product.product_location %}{% endif %}, for example `[email protected]`.
 
+CODEOWNERS paths are case sensitive, because {% data variables.product.prodname_dotcom %} uses a case sensitive file system. Since CODEOWNERS are evaluated by {% data variables.product.prodname_dotcom %}, even systems that are case insensitive (for example, macOS) must use paths and files that are cased correctly in the CODEOWNERS file.
+
+{% if codeowners-errors %}
+If any line in your CODEOWNERS file contains invalid syntax, that line will be skipped. When you navigate to the CODEOWNERS file in your repository on {% ifversion ghae %}{% data variables.product.product_name %}{% else %}{% data variables.product.product_location %}{% endif %}, you can see any errors highlighted. A list of errors in a repository's CODEOWNERS file is also accessible via the API. For more information, see "[Repositories](/rest/reference/repos#list-codeowners-errors)" in the REST API documentation.
+{% else %}
 If any line in your CODEOWNERS file contains invalid syntax, the file will not be detected and will not be used to request reviews.
+{% endif %}
 
-CODEOWNERS paths are case sensitive, because {% data variables.product.prodname_dotcom %} uses a case sensitive file system. Since CODEOWNERS are evaluated by {% data variables.product.prodname_dotcom %}, even systems that are case insensitive (for example, macOS) must use paths and files that are cased correctly in the CODEOWNERS file.
 ### Example of a CODEOWNERS file
 ```
 # This is a comment.

content/rest/reference/permissions-required-for-github-apps.md

@@ -348,6 +348,9 @@ _Traffic_
 - [`GET /repos/:owner/:repo/check-suites/:check_suite_id`](/rest/reference/checks#get-a-check-suite) (:read)
 - [`GET /repos/:owner/:repo/check-suites/:check_suite_id/check-runs`](/rest/reference/checks#list-check-runs-in-a-check-suite) (:read)
 - [`POST /repos/:owner/:repo/check-suites/:check_suite_id/rerequest`](/rest/reference/checks#rerequest-a-check-suite) (:write)
+{% if codeowners-errors %}
+- [`GET /repos/:owner/:repo/codeowners/errors`](/rest/reference/repos#list-codeowners-errors) (:read)
+{% endif %}
 - [`GET /repos/:owner/:repo/commits`](/rest/reference/commits#list-commits) (:read)
 - [`GET /repos/:owner/:repo/commits/:sha`](/rest/reference/commits#get-a-commit) (:read)
 - [`GET /repos/:owner/:repo/commits/:sha/check-runs`](/rest/reference/checks#list-check-runs-for-a-git-reference) (:read)

data/features/codeowners-errors.yml

@@ -0,0 +1,5 @@
+versions:
+  fpt: '*'
+  ghec: '*'
+  ghes: '>=3.5'
+  ghae: 'issue-6078'