$ git clone -n https://src.fedoraproject.org/rpms/gnome-epub-thumbnailer.git /var/lib/mock/f41-build-836161-158780/root/chroot_tmpdir/scmroot/gnome-epub-thumbnailer
Cloning into '/var/lib/mock/f41-build-836161-158780/root/chroot_tmpdir/scmroot/gnome-epub-thumbnailer'...
$ git fetch origin 59edb8d0cc21e6056bbbb13976768f298e82ab54:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/gnome-epub-thumbnailer
 * [new ref]         59edb8d0cc21e6056bbbb13976768f298e82ab54 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 59edb8d Update to 1.8