What exactly provides Print to PDF "printer"?

I am trying to have a sandboxed (firejail) instance of okular be able to print to the “Print to PDF” pseudo printer. But the list of printers in the print dialog is empty.

I’m not sure what provides that “printer”. My system doesn’t have cups or even /etc/cups (it does have libcups). I am at a loss on what I must allow for the sandboxed instance to restore access to print to PDF.

QT docs are hard to follow to find actual implementation details

Likley a combination of ghostscript and cups-pdf (which depnds on it) or similar. It has nothing to do with the toolkit or desktop GUI, I think.

Likley a combination of ghostscript and cups-pdf (which depnds on it) or similar. It has nothing to do with the toolkit or desktop GUI, I think.

that’s not what i’ve read on the QT docs (linked on the 1st post). It clearly says that QT provides PDF creation/rendering support. But offer zero clues besides API interfaces.

I’ve found a really old blog post where they say they ported some pdf library. But i bet they already moved to something else. And none of the info i’ve found explain why I have that printer without the firejail sandbox, and I do not have it with the sandbox (using firejail git and arch provided okular profiles)

Only cups package I have on the system is libcups. nothing else (the KDE printer setting just say “no backend” or something to that end. Yet, all apps have the Print to PDF pseudo-printer.

In fact, some (outdated) places suggest adding a Print to PDF printer in CUPs to use different generators than QT to work around bugs.

any other suggestions? i’m lost on this still

Best i could find was that it depends on user dbus, but haven’t found docs on it.