Ask HN: What are some great retro computing projects to contribute to?

You might want to get in touch with the Computer History Museum to see if they have anything you're interested in.

http://www.computerhistory.org/getinvolved/

And while this group is in Tasmania, maybe they could use the help.

http://www.retrocomputingtasmania.com/

Leopard-WebKit is a version of WebKit targeting PowerPC Macs, including the still-very-useful G5 towers (mine has 8GB RAM!) to enable modern web browsing on those machines.

https://sourceforge.net/projects/leopard-webkit/

CrowdSupply funding for Retro-uC: open silicon microcontroller with Z80, MOS6502, and M68K cores ;)

https://www.crowdsupply.com/chips4makers/retro-uc

You can help transcribe the code from the original Apollo Guidance Computer: https://github.com/chrislgarry/Apollo-11

I would wait until this is resolved before contributing: https://github.com/chrislgarry/Apollo-11/pull/324

It's very likely to be a non-issue, but then again it might be (if it is not public domain..)

TempleOS has a fork called "Shrine"