$ git clone -n https://src.fedoraproject.org/rpms/perl-Authen-U2F.git /var/lib/mock/f39-build-1602617-38571/root/chroot_tmpdir/scmroot/perl-Authen-U2F
Cloning into '/var/lib/mock/f39-build-1602617-38571/root/chroot_tmpdir/scmroot/perl-Authen-U2F'...
$ git fetch origin e63159f56bb573c58c8c9d1df8ac3a4f2281a625:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/perl-Authen-U2F
 * [new ref]         e63159f56bb573c58c8c9d1df8ac3a4f2281a625 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at e63159f Initial import