This is github.com/PaperMC/Velocity but with the pure intent on allowing chat modifications (from plugins).
This simply allows plugins to act like they did before 1.19.1 on 1.19.1+ clients.
I (Quaintified) simply deleted the code that kicks you and disallows this to function properly. The code was there (for clients previous to 1.19.1), but was just "turned off" -- so to speak -- for 1.19.1 clients and above.
Not that I know of yet. I have been using this on my server (with active clients) for several months without any issues, but if you find any, please let me know!
Message me on Discord at Quaint#0001 or (preferably) report it on the Streamline Hub Discord server here: https://dsc.gg/streamline
I do not own any of the code in this project, I simply fixed an issue with the current branch of the original author's code (by deleting some of the code). You can find the original author's GitHub page here: https://github.com/PaperMC/Velocity