Git documents .gitignore as a rule set for intentionally untracked files. It does not affect files already tracked. If a local configuration continues appearing in changes after you add a pattern, first inspect whether Git already tracks it instead of adding broader patterns that hide unrelated work.

If the team agrees that the file should remain local, back it up and review the exact path. The documented git rm --cached option removes a path from the index while leaving the working-tree file alone. Preview with --dry-run and use an exact path after --; do not use a broad recursive removal for one file.

Add the appropriate ignore pattern and inspect the staged difference before committing. The change tells future commits to stop tracking that file; it does not remove copies in earlier commits or elsewhere. Other contributors need coordination because a repository-level removal changes what subsequent checkouts contain.

If the file contained an exposed credential, ignoring it is not remediation: revoke or rotate that credential through the provider and follow the repository owner’s incident process. History rewriting is a separate coordinated action, not a routine cleanup step here. This guide does not execute any command or delete any repository data.