Ah, so we need to set noreferrer because Firefox doesn't support noopener?
It seems to support it according to MDN. But this confuses me:
Before Firefox 63, rel="noopener" created windows with all features disabled by default. Starting with Firefox 63, these windows have the same features enabled by default as any other window.
So I guess Firefox "supports" noopener but not in the ways we want? This sounds like it actually does nothing 🤔