$ git clone -n https://src.fedoraproject.org/rpms/perl-Crypt-U2F-Server.git /var/lib/mock/f41-build-1250889-22988/root/chroot_tmpdir/scmroot/perl-Crypt-U2F-Server
Cloning into '/var/lib/mock/f41-build-1250889-22988/root/chroot_tmpdir/scmroot/perl-Crypt-U2F-Server'...
$ git fetch origin 7a876e575ad0b44f7f24b2955caccd09445b70d1:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/perl-Crypt-U2F-Server
 * [new ref]         7a876e575ad0b44f7f24b2955caccd09445b70d1 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 7a876e5 Perl 5.40 rebuild