$ git clone -n https://src.fedoraproject.org/rpms/kf6-kcalendarcore.git /var/lib/mock/f40-build-2485226-61642/root/chroot_tmpdir/scmroot/kf6-kcalendarcore
Cloning into '/var/lib/mock/f40-build-2485226-61642/root/chroot_tmpdir/scmroot/kf6-kcalendarcore'...
$ git fetch origin 0d28ee6a6a52f2cb148907a72b0abe809e6e17a3:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/kf6-kcalendarcore
 * [new ref]         0d28ee6a6a52f2cb148907a72b0abe809e6e17a3 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 0d28ee6 6.0.0