It opens the file. In which particular way it opens that file of course depends on the system in question – I don’t have Emacs on my phone, I don’t want xdg-ope

It opens the file. In which particular way it opens that file of course depends on the system in question – I don’t have Emacs on my phone, I don’t want xdg-open to attempt to open text files with Emacs on my phone. Whether or not the apparent distribution default of opening text files with Firefox makes sense is an issue somewhat orthogonal to whether xdg-open works – in that particular case it may have been misconfigured to open files with Firefox, but that doesn’t mean it a) didn’t open the file (it did) nor b) in a completely unreasonable way (the file was still displayed and such).