What are you on that Firefox doesn't have a built-in print-to PDF? On GNU/Linux, I've got a "Print to File" printer that lets me select between PDF and Postscript, even though I don't have cups-pdf installed.

Thanks! That "Print to File" is provided by the operating system, not Firefox. I'm on Windows 7, where the operating system doesn't provide this. Yet Chrome provides it itself.

It's a CUPS feature on macOS and Linux, not a Firefox feature.

I used to use it as a CUPS feature, but as I said: I don't have cups-pdf installed, and indeed, I don't have CUPS installed at all. Perhaps it is being provided by some system library (perhaps libcups), but not by CUPS itself.

Actually, it's a "gtkprint" feature. You don't have to install anything separately. But still something built-in into the operating system.

Firefox has the option to save to PDF (on macOS at least). http://imgur.com/a/pKOPU

Thanks! Might this be provided by the operating system as well (instead of Firefox)?