$ git clone -n https://src.fedoraproject.org/rpms/utf8cpp.git /var/lib/mock/f40-build-2225169-52806/root/chroot_tmpdir/scmroot/utf8cpp
Cloning into '/var/lib/mock/f40-build-2225169-52806/root/chroot_tmpdir/scmroot/utf8cpp'...
$ git fetch origin 1734b0da5d347713f17c51ee7bc6b7ae4e072a2c:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/utf8cpp
 * [new ref]         1734b0da5d347713f17c51ee7bc6b7ae4e072a2c -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 1734b0d update to 4.0.5 (resolves rhbz#2245744)