We needed a way to have annotated content which we are able to do with the tippy.js library.
The design made it so we needed a slide out panel (modal) to display the annotated content and the tooltip content in the modal.
The footnotes module got us 90% to our solution.
Create an option to use footnotes as annotated text instead of as footnotes.
Codepen showing different colored annotated text with a tooltip.
'#type' => 'textfield' to '#type' => 'text_format' Active
4.0
Footnotes
Hmmm very interesting! I'm not sure we could support that in here though but I would be open to accepting contributions for refactors that allow you to extend it yourselves easier, e.g via another contrib module.
You should consider though making them not mutually exclusive. Someone could want to do both things right?