docs: view files from private data directory of Android app (#1907)

* docs: view files from private data directory of Android app

* naming

* spelling

* spelling

* change

docs/ANDROID.md

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+# Accessing files in Android app
+
+SimpleX uses databases and stores its preferences inside private data directory in Android. The directory contains:
+- databases
+- sent and received files
+- temporary files that will be deleted when not needed
+- user preferences.
+
+
+If you want to view what's stored inside SimpleX data directory you need to have:
+- Unix-based operating system (or [MinGW](https://www.mingw-w64.org/downloads/) on Windows)
+- ADB (Android Debug Bridge) tool installed on a computer ([download it here](https://developer.android.com/studio/releases/platform-tools) and install)
+- your device connected via USB or Wi-Fi to the computer.
+
+## The process:
+- open SimpleX, go to `Database passphrase & export`, enable `App data backup`. This will make other steps working
+- _optional_: if you want to view database contents, change database passphrase from random to yours. To do this, stop a chat in `Database passphrase & export` screen, open `Database passphrase`, enter new passphrase and confirm it, then update it. Do not forget it, otherwise you'll lose all your data in case passphrase will be asked again later
+- open a terminal emulator (Windows CMD/Powershell will not work) and change directory to the one you want to use for storing the backup:
+
+```bash
+cd /tmp  # just an example
+```
+Then run the following:
+```bash
+adb -d backup -f chat.ab -noapk chat.simplex.app && 
+tail -n +5 chat.ab > chat.dat && 
+printf "\x1f\x8b\x08\x00\x00\x00\x00\x00" | cat - chat.dat > chat.gz && 
+tar -xvzf chat.gz
+```
+
+Now unlock the device and confirm a backup operation without using a password for encryption, otherwise the commands will not work.
+
+After that the backup should be ended. If you see an error saying `tar: Error is not recoverable: exiting now` but before that you have printed some file names, don't worry, it's ok.
+
+Now the backed-up files will be inside `./apps/chat.simplex.app/`.
+
+Please, note, that if you use a modern version of SimpleX, the databases will be encrypted, and you'll not be able to view contents of them without using `sqlcipher` application and without knowing decryption passphrase (you need to change it to yours from randomly generated in the app firstly).
+
+Please, follow [SQL.md](./SQL.md) guide for more info of how to decrypt your databases and to make queries to them.

docs/SQL.md

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+# Decrypting databases
+
+In order to view database data you need to decrypt it first. Install `sqlcipher` using your favorite package manager and run the following commands in the directory with databases:
+```bash
+sqlcipher files_chat.db
+pragma key="youDecryptionPassphrase";
+# Ensure it works fine
+select * from users;
+```
+
+If you see `Parse error: no such table: users`, make sure you entered correct passphrase, and you have changed passphrase from random in Android app (if you got this database from Android device, of course).
+
 # Accessing message history via SQL queries
 
 You can run queries against `direct_messages`, `group_messages` and `all_messages` (or their simpler alternatives `direct_messages_plain`, `group_messages_plain` and `all_messages_plain`), for example: