$ git clone -n https://src.fedoraproject.org/rpms/jaxb-istack-commons.git /var/lib/mock/f40-build-2103870-50564/root/chroot_tmpdir/scmroot/jaxb-istack-commons
Cloning into '/var/lib/mock/f40-build-2103870-50564/root/chroot_tmpdir/scmroot/jaxb-istack-commons'...
$ git fetch origin c10df77738e0b70f1d3406b7e9610579a21ba6a9:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/jaxb-istack-commons
 * [new ref]         c10df77738e0b70f1d3406b7e9610579a21ba6a9 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at c10df77 Update javapackages test plan to f40