$ git clone -n https://src.fedoraproject.org/rpms/dietlibc.git /var/lib/mock/f39-build-1793293-41752/root/chroot_tmpdir/scmroot/dietlibc
Cloning into '/var/lib/mock/f39-build-1793293-41752/root/chroot_tmpdir/scmroot/dietlibc'...
$ git fetch origin a202e428764d1868dbe4832101ac3eeb3d70bec8:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/dietlibc
 * [new ref]         a202e428764d1868dbe4832101ac3eeb3d70bec8 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at a202e42 Fix FTBFS