$ git clone -n https://src.fedoraproject.org/rpms/re2.git /var/lib/mock/f45-build-34378-685/root/chroot_tmpdir/scmroot/re2
Cloning into '/var/lib/mock/f45-build-34378-685/root/chroot_tmpdir/scmroot/re2'...
$ git fetch origin 5189e540bb92582d95feaff4a72fa34efe0ecd48:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/re2
 * [new ref]         5189e540bb92582d95feaff4a72fa34efe0ecd48 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 5189e54 Simplify setting Boolean CMake options based on build conditionals