Cryptic? - How? I'm being as precise as I can be
That's a temporary workaround that will only work on SDK 29 targets. You should have read it here
There are several versioned components that affect the compilation process and the runtime behavior of our apps. The purpose of this tutorial is to explain the differences between them and help you choose which version to use. Each Android version is mapped to an api level. You can see this...
www.b4x.com
There is no need to manually add the "AddPermission" lines to the manifest. B4A should add them and you automatically get read permission if you ask for write permission.