To generate PDFs with hyperlinks requires code in Firefox or an add-on to build the document rather than sending it to a printer driver.
- Adobe’s “Create PDF” extension is a proprietary WebExtensions example (bundled with Acrobat Standard or Pro, but not Reader)
- The legacy extension Print Pages to PDF did it using the wkhtmltopdf library, which might be how Safari and Chrome do it (Possible Update for Print Pages to PDF Add-on)
Note: The tabs.SaveAsPDF() method available to extensions emulates printing, so that doesn’t help with this problem.