Can someone tell me what was that version of FF
Either I install "that" old version (if possible) or switch to an other browser.
I doubt if there are any other browsers that can save as pdf. However, on Windows 10 it is easy to create a pdf file because Microsoft gives you pdf "print driver" for free. All you do is to print the webpage on your pdf printer which Microsoft installs by default. Search for "Microsoft Print to pdf" on your machine if you are using Windows 10.
With over 1.2 billion devices now running Windows 10, customer satisfaction is higher than any previous version of windows.
Chromium on Linux can save a page as pdf, so I expect Chrome can.
On Windows there aren't any browsers that can do this. I don't
know what the OP is using but I suspect he must be using Windows
with some flavours! His user agent is isn't telling us anything.
How do you do that in Chrome? I have Chrome and see no option to save page as PDF.
In Windows there is no "Save as . ." option. You can print to
pdf (as I stated in my previous posts) but this was not what was
asked and the OP wants "Save as . . " option and for that he'll
need to change the Mozilla Code and recompile it for his needs. Â
Not easy for people who are not coders by profession.
Maybe a "save as pdf" add-on.
There is no need for Add-Ons when you can Print to pdf. I have avoided Add-Ons for years and I encourage other users to do the same. Add-Ons can result in all sorts of problems when Windows and Firefox can do most things for everyday use without any Add-Ons.
For most users all they want is stable system that can enable
them to do their work efficiently and Firefox and Windows can do
exactly that.
I can't find any reference to it in the 84.0 or 85.0 release notes, when was it introduced?
ff 81 ??
It's optional. Users need to tweak their config to true.  The
main changes are new Print Preview window.