$ git clone -n https://src.fedoraproject.org/rpms/dtk6gui.git /var/lib/mock/f42-build-side-1-3585938-46912/root/chroot_tmpdir/scmroot/dtk6gui
Cloning into '/var/lib/mock/f42-build-side-1-3585938-46912/root/chroot_tmpdir/scmroot/dtk6gui'...
$ git fetch origin 29409ce598b6b7844a1147048351250f60202b22:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/dtk6gui
 * [new ref]         29409ce598b6b7844a1147048351250f60202b22 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 29409ce Fix build (missing header)