$ git clone -n https://src.fedoraproject.org/rpms/kdiff3.git /var/lib/mock/f39-build-1540489-36475/root/chroot_tmpdir/scmroot/kdiff3
Cloning into '/var/lib/mock/f39-build-1540489-36475/root/chroot_tmpdir/scmroot/kdiff3'...
$ git fetch origin eb79a6db4b5374db33b36c97ccdd70adb091c897:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/kdiff3
 * [new ref]         eb79a6db4b5374db33b36c97ccdd70adb091c897 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at eb79a6d Update to 1.10.6.