$ git clone -n https://src.fedoraproject.org/rpms/libproxy.git /var/lib/mock/f39-build-1575065-37921/root/chroot_tmpdir/scmroot/libproxy
Cloning into '/var/lib/mock/f39-build-1575065-37921/root/chroot_tmpdir/scmroot/libproxy'...
$ git fetch origin 7abcff4b4a88c43e2e332988e516d25c11276687:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/libproxy
 * [new ref]         7abcff4b4a88c43e2e332988e516d25c11276687 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 7abcff4 Install a versioned library symlink (#2247508)