$ git clone -n https://src.fedoraproject.org/rpms/dtk6gui.git /var/lib/mock/f42-build-868475-176120/root/chroot_tmpdir/scmroot/dtk6gui
Cloning into '/var/lib/mock/f42-build-868475-176120/root/chroot_tmpdir/scmroot/dtk6gui'...
$ git fetch origin 39f5a74420514ebd3d540e383c3ce9aaa269accb:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/dtk6gui
 * [new ref]         39f5a74420514ebd3d540e383c3ce9aaa269accb -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 39f5a74 6.0.25