MyBB Community Forums

Im just curious why these files have to be writeable by public?
Also the cache directory. Why must this be writeable to public?

Because 757 and 775, which give less permissions than 777, won't work on all servers, so we say to use 777 as that's clearer for people and will make sure it'll work. If 775/664 works for folders/files then you can use that.

settings.php, config.php, and the cache directory need to be writable by the web server. Many people run their web server as nobody, so that means making those files and that directory world-writable.