Problem: There are some links that force download PDFs on your device and it is annoying to delete them every time especially when you just want to read the contents. I understand that some are intentional download links but it would be nice to view and then save them to disk.
Solution: A feature/setting to preview all PDF download links instead of downloading and then the user can download after they are sure they want to save to disk. Other browsers don't have this yet so it would be nice to have this as an edge for Firefox. Lastly, for some people who view tons of PDFs per day, this would be a great feature and would improve the experience.