Copy is not created on Linux

[Varbin]

Original report: https://social.tchncs.de/@kluergen/114151638153743680

Temporary solution: Ensure your designated filename ends explicitly ends with .pdf.

[Varbin]

I can verify this.
It does work on wine, so I guess it is a desktop portals issue.

[Varbin]

Okay, this error occures if the file does not end with '.pdf' because... other filetypes are not implemented, and a default extension is not set with portals...