link solutions/answers back to original in html

[Tanaquil18]

When answers/solutions are not visible in context but instead are added to the backmatter or somewhere else, I would like to be able to quickly get from an answer in the back to the problem in-context.

This is already implemented in pdf where the type/number of the activity or exercise is a link back to the problem in context. Another option could be to mimic what happens when automatic lists of theorems or definitions or interactive problems are created: there is an "in-context" link.