$ git clone -n https://src.fedoraproject.org/rpms/gnome-shell-extensions.git /var/lib/mock/f45-build-11550-432/root/chroot_tmpdir/scmroot/gnome-shell-extensions
Cloning into '/var/lib/mock/f45-build-11550-432/root/chroot_tmpdir/scmroot/gnome-shell-extensions'...
$ git fetch origin 6c6f76ed854d58f28bb3ab603909449e5693e703:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/gnome-shell-extensions
 * [new ref]         6c6f76ed854d58f28bb3ab603909449e5693e703 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 6c6f76e Update to 51.0