$ git clone -n https://src.fedoraproject.org/rpms/rubygem-http_parser.rb.git /var/lib/mock/f40-build-733966-105612/root/chroot_tmpdir/scmroot/rubygem-http_parser.rb
Cloning into '/var/lib/mock/f40-build-733966-105612/root/chroot_tmpdir/scmroot/rubygem-http_parser.rb'...
$ git fetch origin 5729a2d50342875e0691cb2bfea6ed3349135343:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rubygem-http_parser.rb
 * [new ref]         5729a2d50342875e0691cb2bfea6ed3349135343 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 5729a2d update to new version 0.8.0