$ git clone -n https://src.fedoraproject.org/rpms/rubygem-xmlparser.git /var/lib/mock/f40-build-2250390-54049/root/chroot_tmpdir/scmroot/rubygem-xmlparser
Cloning into '/var/lib/mock/f40-build-2250390-54049/root/chroot_tmpdir/scmroot/rubygem-xmlparser'...
$ git fetch origin 062bd3cfcc8f3389eede98f47a4b99b300f4f800:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rubygem-xmlparser
 * [new ref]         062bd3cfcc8f3389eede98f47a4b99b300f4f800 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 062bd3c Fix C compatibility issues (#2256626)