$ git clone -n https://src.fedoraproject.org/rpms/rpm.git /var/lib/mock/f40-build-760981-121325/root/chroot_tmpdir/scmroot/rpm
Cloning into '/var/lib/mock/f40-build-760981-121325/root/chroot_tmpdir/scmroot/rpm'...
$ git fetch origin 6fcc9727332425b14aca14cb2c4d9f0b34aef1d4:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rpm
 * [new ref]         6fcc9727332425b14aca14cb2c4d9f0b34aef1d4 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 6fcc972 Update to 4.19.1 (https://rpm.org/wiki/Releases/4.19.1)