SUMMARY
In any KDE application - When printing to the "Print To File (PDF)" device, the paper size defaults to A4.  It can be changed to another size, but this must be done for every print job.

This device does not appear under System Settings - Printers.  Other printers that do show up there have been set to default to US Letter paper size.


STEPS TO REPRODUCE
1. Open any KDE application.  Gwenview, for example, though it happens in all KDE apps.
2. Open a document.
3. Pull down File and choose Print.
4. Choose the "Print To file (PDF)" device from the list of printers.
5. Click the Properties button.  Observe that the paper size is A4.  Change the paper size to something else.
6. Run the print job.
7. Repeat and notice that the paper size is once again A4.

OBSERVED RESULT
The default paper size for the "Print To File (PDF)" device is always A4.  The default cannot be changed.

EXPECTED RESULT
Some way should be provided to change the default paper size for the "Print To File (PDF)" device.

SOFTWARE/OS VERSIONS
Operating System: Fedora Linux 35
KDE Plasma Version: 5.24.2
KDE Frameworks Version: 5.91.0
Qt Version: 5.15.2
Kernel Version: 5.16.9-200.fc35.x86_64 (64-bit)
Graphics Platform: X11
Processors: 4 × Intel® Core™ i5 CPU 760 @ 2.80GHz
Memory: 15.6 GiB of RAM
Graphics Processor: NVIDIA GeForce GT 710/PCIe/SSE2

ADDITIONAL INFORMATION