$ git clone -n https://src.fedoraproject.org/rpms/regina-rexx.git /var/lib/mock/f40-build-2232471-53334/root/chroot_tmpdir/scmroot/regina-rexx
Cloning into '/var/lib/mock/f40-build-2232471-53334/root/chroot_tmpdir/scmroot/regina-rexx'...
$ git fetch origin 817530dba4b95debd226f324ecf576bc46c72f90:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/regina-rexx
 * [new ref]         817530dba4b95debd226f324ecf576bc46c72f90 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 817530d Fix C compatibility issues in the configure script