$ git clone -n https://src.fedoraproject.org/rpms/libxmlb.git /var/lib/mock/f41-build-side-1-2647736-27311/root/chroot_tmpdir/scmroot/libxmlb
Cloning into '/var/lib/mock/f41-build-side-1-2647736-27311/root/chroot_tmpdir/scmroot/libxmlb'...
$ git fetch origin d58118a91c03f078b8ea8b578d9e3169b46eed6b:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/libxmlb
 * [new ref]         d58118a91c03f078b8ea8b578d9e3169b46eed6b -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at d58118a Disable libstemmer on RHEL