$ git clone -n https://src.fedoraproject.org/rpms/firefox.git /var/lib/mock/f45-build-46521-839/root/chroot_tmpdir/scmroot/firefox
Cloning into '/var/lib/mock/f45-build-46521-839/root/chroot_tmpdir/scmroot/firefox'...
$ git fetch origin 3ce20ad804da91fe25e137770fa789dc0bc8cad9:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/firefox
 * [new ref]         3ce20ad804da91fe25e137770fa789dc0bc8cad9 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 3ce20ad Merge branch 'main' into f45