Greasy Fork is available in English.
Changes "Upload" link to open a printable viewer (print to PDF)
< Feedback on Scribd Print and Download
If that's actually the case then it's most likely been removed on Scribd's end. However I just tried it out and it's still working as intended for me so I'm not sure what to say to you.
I will admit that this does not work for every document. I don't know precisely why that is, but it appears to have to do with the contents of the document itself.
To be sure. When you click "Print" you are then supposed to use your own Print to PDF device on your computer. i.e., click Print -> (Standard Quality) Print -> (choose printer, for this example I will use:) Microsoft Print to PDF.
If it still does not work for you and you are using the 64-bit version of Firefox. Try using Firefox 32-bit. For some reason I have encountered issues with 64-bit in the past.
No good
once activated, the script will show you the flash image document, but the print function to send to pdf or actually print doesnt work. If you are thinking of waiting for a fix, dont waste your time. According to the author-
v1.7 2017-03-06 - Added /document/ address. Nothing else changed. If it's broken I don't have time to fix it.