[A] Internal Actions Marketplace
The reason for having an internal actions marketplace is to have a central location for all the actions that can be used inside our production organization. This is to prevent any actions from the public marketplace from being used in our production organization, without being checked for security risks first.
[B] Allow Marketplace actions by verified creators: You can allow all GitHub Marketplace actions created by verified creators to be used by workflows. When GitHub has verified the creator of the action as a partner organization, the badge is displayed next to the action in GitHub Marketplace.
[C] You can enable specific actions for the organization by identifying them and providing version control, ensuring only trusted versions are used in workflows.
Reference:
https://devopsjournal.io/blog/2021/10/14/GitHub-Actions-Internal-Marketplace
https://docs.github.com/en/enterprise-cloud@latest/organizations/managing-organization- settings/disabling-or-limiting-github-actions-for-your-organization