Beeper open sourced the iMessage bridge about 2 days ago: https://blog.beeper.com/p/imessage-and-phone-registration-ar... (although I realized one hour ago, that's why I posted it!)

Oops, you're right, I mixed up the posts. This is the actual duplicate, still has 700 plus comments so I was correct that this is a duplicate of a story that has already been covered extensively:

https://news.ycombinator.com/item?id=38722246

Just based on the most cursory look, which took less time than it took you to write your comment (considering the links you added taking more time than typing…), they are different repositories by different people for different things.

I mixed up the posts. There have been a lot of high ranking Beeper posts lately. The one I was thinking of only had 700 comments, but I think it's fair to say that this is a duplicate:

https://news.ycombinator.com/item?id=38722246