In Firefox, on a normal webpage, you can right click and go Take Screenshot. This allows you to take a scrolling screenshot as well, which not possible using standard screenshot software like Greenshot or Snipping Tool. Thumbs up!
I just found that you can't do a scrolling screenshot for a PDF - you can only screenshot the visible parts.
Probably a very niche use case but would've come in handy as I had to OCR some images in a PDF file today, and Firefox OCR extensions were unable (or unwilling?) to work in PDF view, so I screenshotted the PDF file then opened the .JPG in Firefox again. OCR tools were then able to do their thing.