A guide for using the basics of SAF (Storage Access Framework) for all Android versions, to overcome the many file restrictions Android has placed upon AppInventor developers.
This is just about SAF, so please keep any comments related to that. It is not about other aspects or methods for the android file system.
Well done!
I personally had given up on writing extensions because of the confusion that was generated in the implementation of the Android file system in MitAppInventor2