I know exactly how difficult it is. I was part of the cleanup crew who stayed back to opensource wave after google decided to pull the plug. My name is all over the opensourced Google Wave ("Wave in a box") codebase. We rewrote the whole data layer so you could run it without google's infra. That took a nontrivial amount of engineering time - a month or two if memory serves.

> So open sourcing just jamboard specific code and nothing else even if possible wouldn’t build or be really useful.

Oh, it definitely wouldn't build. But you'd be surprised how resourceful opensource developers can be when they have a clear scope & clear spec to work towards. This sort of work is akin to making the world's simplest emulator for a video game console - except you only need to get "one game" to run, and you have its source code and you can change the code as much as you like. Its fun, satisfying work.

Obviously you're rolling the dice on whether or not anyone from the community would step up and do that work on your behalf. But the alternative is killing your product entirely. The opensourced wave died because we didn't grow an opensource community who understood & wanted to maintain the codebase. Looking back, we might have done a better job of that if we didn't do all the work ourselves to make it usable first.

Mind you, I have no idea how the community at large would react to google releasing broken source code. They might complain even more than the service just going dark. But I can still dream.