I'm looking to import my uBlock Origin settings from my desktop PC, which is in a text file, to uBlock Origin in Firefox for Android.
The issue is: When I click on the 'Restore from file...' button on uBlock Origin in Firefox Android, I only get prompted to choose between camera / image apps:
In a Windows PC, clicking on that button will open up an Explorer window allowing you to select a text file to import. I can't import a text file with any of the above apps shown. Is there an app I should install to allow this? How should I configure it?
Details: I have Google Drive and ES File Explorer installed. This is on Android 4.4.2, Firefox for Android 44.0, uBlock Origin 1.5.5.

image/*for unknown reason. – Andrew T. Feb 10 '16 at 08:51text/plain, see source code. I need to investigate why this happens. – R. Hill Feb 10 '16 at 12:30