A composite action is identified by its action metadata file. In action.yml or action.yaml, the runs section must define using: " composite " . This tells GitHub Actions that the action is a composite action made from one or more reusable workflow steps. Option A is incorrect because Dockerfile and package.json files do not identify a composite action; they are usually associated with Docker or JavaScript-based projects. Option C is wrong because repository naming has no technical meaning in action classification. Option D is also wrong because an init.sh file is merely a script and does not define the action type. GitHub’s metadata syntax states that composite actions require runs.using to be set to composite.