[harporoeder]

There is a mechanism for this called portals (1) available in flatpak. It gets integrated into the GUI toolkit, and certain applications are not supported. It is useful for things like accessing files from outside the default sandbox.

1. https://docs.flatpak.org/en/latest/portal-api-reference.html

[its-summertime]

specifically, anything that uses the generic GTK/Qt way of accessing files via the file chooser will automagically use the portal

Anything that tweaks on that, most notably Electron, will not use the portal

[akvadrako]

That's a choice of Electron - it could and should use portals.