By default, where will secret scanning look in a repository in order to execute its...

GitHub secret scanning examines the repository comprehensively rather than limiting analysis to selected files or dependency metadata. GitHub states that secret scanning scans the entire Git history across all branches for supported secrets. Consequently, both current files and historical versions of files can be inspected, which is why simply deleting a leaked credential in a later commit does not eliminate the security risk. The feature searches repository content for supported provider, generic, and other enabled secret patterns. Dependencies themselves are handled primarily through dependency graph and Dependabot functionality and are not a secret-scanning scope category. Therefore, the correct selections are all branches, the full commit history, and all files in the repository.