Internal link preview
Many PDF documents contain internal links. When clicking on these, the user is taken to another part of the document. It would be incredibly useful to me and my colleagues if there was a 'preview link' option. Perhaps this could work by hovering the mouse over the link, and the preview to the link pops up in a small temporary window, allowing you to quickly view the link, without redirecting to a different page.
The motivation for this is as follows: In mathematical sciences, these internal links often refer to equations earlier in the document, which are being combined to create new results. It can be difficult and frustrating to constantly scroll up and down, to check a calculation, and I often lose my place. This would be the digital equivalent of having two book pages open at the same time, and would make checking calculations so much easier!