Comprehensive and Detailed Explanation:
For code scanning to be triggered on a specific branch, the branch must contain the appropriate workflow file, typically located in the .github/workflows directory. This YAML file defines the code scanning configuration and specifies the events that trigger the scan (e.g., push, pull_request).
Without the workflow file in the branch, GitHub Actions will not execute the code scanning process for that branch. The repository's visibility (private or public), the status of secret scanning, or the activity level of developers do not directly influence the triggering of code scanning.