$ git clone -n https://src.fedoraproject.org/rpms/postfix.git /var/lib/mock/f41-build-833852-14943/root/chroot_tmpdir/scmroot/postfix
Cloning into '/var/lib/mock/f41-build-833852-14943/root/chroot_tmpdir/scmroot/postfix'...
$ git fetch origin aa0f226f942f521863b0829a367844c1464d9ddc:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/postfix
 * [new ref]         aa0f226f942f521863b0829a367844c1464d9ddc -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at aa0f226 Eliminate use of obsolete %patchN syntax (#2283636)