$ git clone -n https://src.fedoraproject.org/rpms/gdb.git /var/lib/mock/f42-build-866162-173776/root/chroot_tmpdir/scmroot/gdb
Cloning into '/var/lib/mock/f42-build-866162-173776/root/chroot_tmpdir/scmroot/gdb'...
$ git fetch origin 8d5adc72d172051b5eae90a9ab35956c020bd7a0:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/gdb
 * [new ref]         8d5adc72d172051b5eae90a9ab35956c020bd7a0 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 8d5adc7 Convert RPM suggestion feature into a Python extension