Repository

A repository — usually shortened to "repo" — is the container for a project's code together with its entire history of changes. Every commit ever made to the project lives in the repo, which means you can see exactly what changed, when, and by whom, and return to any previous state.

A repo also holds branches: parallel lines of work that let changes be developed and reviewed before being merged into the main line. This is what makes collaborative, reversible development possible — multiple changes in flight at once, each tracked independently, none of them overwriting the live system until they are ready.

In practice, the repository is the single authoritative copy of a project. Hosting platforms deploy from it, developers (and AI coding tools) work against it, and its history is the audit trail for the software itself.