What does xdg-open actually do?

Gnome-shell user, since a while, my default file manager has been pcmanfm (because it still allows typeahead, which nautilus has dropped a while back).

Except I don’t know what “default file manager” means anymore: I don’t actually remember how I set it - and hence I am unable to set it on another computer, or to reset to nautlius.

I have googled quite a bit, and the most common reply seems to be that one needs to set the handler for the “inode/directory” MIME type via the “xdg-mime” app. Except that if I do

xdg-mime query default inode/directory

I get as output “aalacarte-made-8.desktop”. But again, “xdg-open ~/” (luckily) starts pcmanfm, not alacarte. And by the way, pcmanfm is launched even if I use xdg-open on an sftp URL (arguably not related to the “inode/directory” MIME type).

Another piece of advice I found suggests looking at files in ~/.local/share/applications, specifically mimeapps.list and mimeinfo.cache. But I checked and pcmanfm appears in neither of the two.

Ultimately, I need this answer because for a program I maintain, I want to be able to launch a user’s default file manager.

Thanks for any suggestion.

alacarte-made-8.desktop does not mean that this is the .desktop file of alacarte, but some .desktop file made by alacarte. Maybe that file is for pcmanfm?

Ooops… how could I miss that! Yes, definitely, that file is for pcmanfm.

So in the end the answer of looking at “inode/directory” MIME type was correct.

Sorry for the noise, thanks Sebastian.