[mkmk2]

I wouldn't expect a project like that to go too far, I know of a couple of oss whatsapp clients that got took down, I'd assume when such a component comes online facebook would start causing trouble for them. Matrix uses bots which bridges services with services like signal, that seems to be the easiest way to achieve inter-operability, though idk how usable it is in practice.

[raghav_nautiyal]

It isn't likely Facebook is going to be in favour of such a feature, if it ever comes up. It just seems like it would be something that would give people more of an incentive to move to Signal, since they won't lose their contacts. Not sure how it would work in practice though, and how would Signal ensure the messages aren't going through to WhatsApp. Anyway, this was just a thought.