$ git clone -n https://src.fedoraproject.org/rpms/sirocco.git /var/lib/mock/f40-build-2260857-54424/root/chroot_tmpdir/scmroot/sirocco
Cloning into '/var/lib/mock/f40-build-2260857-54424/root/chroot_tmpdir/scmroot/sirocco'...
$ git fetch origin 477f0c4e88479336e2c4279e99ce726e7c667f52:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/sirocco
 * [new ref]         477f0c4e88479336e2c4279e99ce726e7c667f52 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 477f0c4 Stop building for 32-bit x86