Interesting, thanks!
I used bulletin boards back in the early 90s but had not realised they had continued into the 2000s, and am shocked that a vestige of them remains in my favourite internet forum in 2019
[Sorry about the 'necro' of an old post but I saw it in google search results images and I wondered why there was a Settings icon in the editor...]
It's more than a vestige, if you use
bold,
italics,
font, or image links buttons and then click the BBcode button - which is now
[ ] brackets icon...
...you'll see the BBcode...
If you're typing, it's sometimes easier to just type the BBcode instead of moving your hand to the mouse.
But XenForo, with this default/standard setup, does not support the superscript/subscript codes.
Apparently it needs to use css.extra or something.
x[sup]2[/sup]
Bulletin boards...I had some BB program that was so nice, I miss it.
No way I could remember what it was. It was more fun than usenet...