Kind of like how you can do [in-line links](to link people to a website), allow the user to use the same syntax to create contextual information that appears when the [user mouses over](Similar to alt-text on an image). This way users who know the context won’t have to slog through a tedious wall of text while those who don’t can optionally bring themselves up to speed. For clarity sake in-line context will be a different color to a link, and those on mobile (or desktop) can click it to expand out the contained text as if it was part of the original comment.
EDIT: it might be a good idea to potentially use different syntax so that you can link websites within in-line context.
This is definitely a cool but very niche feature that I and nerds like me would use, but the vast majority of normal* folk never would. So for that reason it’s probably not going to be any kind of priority to add. But hey, in the meantime, we’ve always got footnotes!
* “normal” by Lemming standards, anyway
I find footnotes are extremely clumsy and break the pacing of the sentence. For example, I read your footnote first, and didn’t get the context.