Fork this repo and you should be able to create your own BBCode's on the fly (if you understand how the extension was coded that is).
https://github.com/sijad/flarum-ext-details
It's a good start if you want to jump right into adding more BBCode's.
https://github.com/Ralkage/flarum-ext-details/blob/master/src/Listener/AddBBCode.php
This is where the magic happens so fork it, customize it, debug it, and most importantly, give credit!
Oh and let us know when we can start using it for our projects lol.
