<!--IssueSummary start--> <details> <summary> Everyone can contribute. [Help move this issue forward](https://handbook.gitlab.com/handbook/marketing/developer-relations/contributor-success/community-contributors-workflows/#contributor-links) while earning points, leveling up and collecting rewards. </summary> - [Close this issue](https://contributors.gitlab.com/manage-issue?action=close&projectId=278964&issueIid=526772) </details> <!--IssueSummary end--> ## Context We recently noticed that the `commits_without_merge_commits` and `default_merge_commit_message` fields are not used by the frontend anymore, so we soft-deprecated them in https://gitlab.com/gitlab-org/gitlab/-/merge_requests/182725. These 2 endpoints (`widget.json` and `cached_widget.json`) are called often, and should be limited to only the fields that are in use. ## Goal 1. ~frontend Review all fields from these endpoints and determine if any are no longer needed 2. ~backend Soft deprecate any fields identified in step 1