Default File Manager

[Sander Jansen]

Is there a cross-desktop way of determining the default file manager
to use? I want to show show a specific folder and/or file in the file
manager. I was hoping to perhaps use the mimeinfo.cache /
mimeapps.list / defaults.list to find this out, but not sure how
cross-desktop this really is (and what mimetype to check for:
x-directory, inode-directory?).

Or should I use something more elaborate, like determining the current
desktop environment (is there a standard for doing this, I know some
set DESKTOP_SESSION in the environment) and guess from there.

Thanks,

Sander