$ git clone -n https://src.fedoraproject.org/rpms/java-latest-openjdk.git /var/lib/mock/f40-build-2125562-50779/root/chroot_tmpdir/scmroot/java-latest-openjdk
Cloning into '/var/lib/mock/f40-build-2125562-50779/root/chroot_tmpdir/scmroot/java-latest-openjdk'...
$ git fetch origin 40e24677c5eb7e44c408ab1456dc51f52a93c2c1:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/java-latest-openjdk
 * [new ref]         40e24677c5eb7e44c408ab1456dc51f52a93c2c1 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 40e2467 using generated sources from portables for final debuginfo