Add API Security navigation items (!3583) · Merge requests · GitLab.org / GitLab Docs

Add navigation item to global navigation

Link to the merge request that introduced the new page: gitlab!108878 (merged)
Give the MR a descriptive title.
Optional. Link to the review app showing the new page: https://docs.gitlab.com/ee/user/application_security/api_security/

Note: The docs are live, so I've linked to them instead of the review app.