$ git clone -n https://src.fedoraproject.org/rpms/perl-Tk.git /var/lib/mock/eln-build-side-115067-61052322-6588219/root/chroot_tmpdir/scmroot/perl-Tk
Cloning into '/var/lib/mock/eln-build-side-115067-61052322-6588219/root/chroot_tmpdir/scmroot/perl-Tk'...
$ git fetch origin 97de1d2376c206d34ae7dd4647af6843aaa6329a:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/perl-Tk
 * [new ref]         97de1d2376c206d34ae7dd4647af6843aaa6329a -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 97de1d2 Perl 5.42 rebuild