I have many passwords stored within Firefox, rightly or wrongly, and have come across a few ways to view and print these for future reference.

However, this version seems to be one of the better ones in my opinion without using an Add-On as such . . . . >> Pass Words Displayed << . . . .

To use it, Right click on the words Pass Words Displayed and Save Link As to the Desktop.
On the Desktop, Double click and it opens a browser Window showing your passwords stored for saving or printing.
You will receive a security warning before it opens.