$ git clone -n https://src.fedoraproject.org/rpms/libmediainfo.git /var/lib/mock/f42-build-863053-171350/root/chroot_tmpdir/scmroot/libmediainfo
Cloning into '/var/lib/mock/f42-build-863053-171350/root/chroot_tmpdir/scmroot/libmediainfo'...
$ git fetch origin 8021590051c858cbe4d011fd729b41e5616afb6c:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/libmediainfo
 * [new ref]         8021590051c858cbe4d011fd729b41e5616afb6c -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 8021590 rebuild for tinyxml2