The tcolorbox package

Appendix

The package is partially compatible with tagging. Thanks to Ulrike Fischer, the following works:

Basic tcolorboxes with /tcb/capture mode minipage (this is the standard case). Capture modes hbox and fitbox are not supported yet. The same is true for \tcbox and \tcboxfit.
Upper part and lower part.
Titles of boxes.
Created boxed by \newtcolorbox, etc.
Theorem boxes. Depending on the used /tcb/theorem style, the title is tagged as caption (standard, change standard, plain apart, change apart, margin apart) or not (the other ones).
Breakables tcolorboxes.
Skins like /tcb/enhanced, /tcb/bicolor, etc.

The tagging code inserts additional \par’s before and after a tcolorbox. This may (will) interact with /tcb/before and /tcb/after settings. Especially, /tcb/nobeforeafter will not work as expected.
tcbraster cannot have more than one column, because of the additional \par’s caused by tagging.
Boxed titles will not be tagged.