How does Git’s reference system (refs, HEAD, symbolic refs) work internally?

Git references (refs) are pointers to commits; HEAD is a symbolic ref pointing to the current branch.

Refs are stored in .git/refs and include branches, tags, and remote-tracking refs. HEAD usually points to a branch ref (e.g., refs/heads/main), which in turn points to a commit hash. Symbolic refs allow indirect referencing, enabling branch switching without modifying commit objects. Detached HEAD occurs when HEAD points directly to a commit hash instead of a branch.