$ git clone -n https://src.fedoraproject.org/rpms/rust-mime_guess.git /var/lib/mock/f45-build-43230-801/root/chroot_tmpdir/scmroot/rust-mime_guess
Cloning into '/var/lib/mock/f45-build-43230-801/root/chroot_tmpdir/scmroot/rust-mime_guess'...
$ git fetch origin aa5e614f85cc2e65ac547a8e24db92bc445faa28:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-mime_guess
 * [new ref]         aa5e614f85cc2e65ac547a8e24db92bc445faa28 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at aa5e614 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild