Allow Android apps holding the WRITE_EXTERNAL_STORAGE permission to read and write on the MicroSD card.
This is accomplished by modifying the /system/etc/permissions/platform.xml file to add the group media_rw to the WRITE_EXTERNAL_STORAGE permission's configuration.
This module was only tested on Android 14, but should work on almost all Android versions. The platform.xml file did not suffer any breaking change since Android 4.x.