Comment by cmrdporcupine

I know it's confusing, but things being under the 'google' namespace on GitHub doesn't mean they're maintained by Google. At least not as an official project.

It just means a person working at Google used that avenue to open source them.

Google offers a legal few avenues to allow you to open source your stuff while working there but one of the easiest it just to assign copyright to Google and shove it under their GitHub.

It just means a Googler published it, not that Google itself is maintaining it.

I don't know what the status of flatbuffers is specifically, but I can say I never encountered it in use in the 10 years I worked there. (I use it a lot now on my own things post-Google)