Hello.
May I draw your attention to my post in /lit/ https://boards.guro.cx/dis/koko.php?res=28856 (short formatting string guide (Update 2025a))?
It is slightly more accurate than the BBCode reference (which basically is a good thing to have).
The strikethrough and the spoiler tag are not only mixed up (name and syntax), but — while recognized by the parser — both are not set into action.

I understand that there are more urgent issues. Nevertheless I'd like to list the IMHO most missing formatting strings:
​=​=​Headline​=​=​ (2 equals signs before and after the text) In the source codes of old posts the CSS-class "heading" is still applied, but no more interpreted (see https://boards.guro.cx/dis/koko.php?res=27777) BTW, it would be nice, if the old centered header could be reinstalled too.
​>​ (one closing angle bracket) Quoting is not available. (Old posts: CSS-class "unkfunc" in source code, but "inactive".)
​>​>​>​ (three closing angle brackets) New links to other boards can't be set. Links in old posts are still working.

Is it possible to activate more of the bbcode? And are there substitution options available (e.g. for arrows, dashes, ellipses and, of course, the "40-dash-line)?

And last but not least: Thank you for your hard work. :)