Where does Git store remote tracking branches

Question

I have to Git repos repo1 and repo2. There are three branches master, alpha and beta in repo1.

Answer 1

The refs are probably "packed" in .git/packed-refs.

Answer 2

The information is in .git/config and is updated by tools like git remote when you add or modify remotes. There is a manual page on git-config. If you search for "tracking branches" you'll see details of how they are configured.