git shows theremote andlocal ref information during a fetch. For example:

 * [new branch]          ethomson/nonblocking   -> origin/ethomson/nonblocking

This is not information that users of libgit2 can currently surface since ourupdate_tips callback includes only src/dest OIDs, and thelocal ref name. Nor can one reliably reverse engineer the remote branch name, since a remote configuration could map two remote specs to a local spec. For example:

        fetch = +refs/pull/*/head:refs/remotes/asdf/*        fetch = +refs/heads/*:refs/remotes/asdf/*

In this case, givenrefs/remotes/asdf/foo in theupdate_tips, a caller would have no idea whether the remote wasrefs/pull/foo/head orrefs/heads/foo.

Provide the matching remotegit_refspec so that callers canrtransform themselves into the remote.