Flow was born in the TYPO3 community and first was only thought of as internal rewrite of the core TYPO3 core but soon got a project in its own right. Now Flow has a community itself and is still connected with the huge TYPO3 community.
We track issues and feature request on forge.typo3.org and have a well documented contribution process including code reviews.
The community is growing, more will come. Stay tuned for more community related information, like events.
Meanwhile explore the TYPO3 community and if you are interested join one of the TYPO3 events.