$ git clone -n https://src.fedoraproject.org/rpms/dtk6core.git /var/lib/mock/f42-build-side-1-3586773-46925/root/chroot_tmpdir/scmroot/dtk6core
Cloning into '/var/lib/mock/f42-build-side-1-3586773-46925/root/chroot_tmpdir/scmroot/dtk6core'...
$ git fetch origin 7c5bd5d94d33c9ae26a53c832fd28d45ef8359fd:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/dtk6core
 * [new ref]         7c5bd5d94d33c9ae26a53c832fd28d45ef8359fd -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 7c5bd5d Rebuild (qt6)