This is a demonstration repository for using GitHub Actions to do Continuous Integration (CI).
GitHub Actions run Workflows, which could be used for Continuous Integration, building, testing, deployment, etc. It has access to the GitHub API, so can even be used for issue and pull request management. See the documentation overview for details if they are not explained here.
Workflows run in a dedicated container image on a virtual machine, either builtin to the GitHub hosting, or built and managed yourself. We won't go into details of the self-managed style here.