add documentation for BN_QSETTINGS_POSTFIX

Author: psifertex

docs/guide/index.md

@@ -63,7 +63,7 @@ The following files and folders may be created in the user folder but are not cr
 
 ### QSettings Locations
 
-Some settings such as window locations, saved checkboxes, recent file lists, disassembly settings, dialog histories are stored in `QSettings`.
+Some settings such as window locations, saved checkboxes, recent file lists, disassembly settings, dialog histories are stored in `QSettings`. Note that the `BN_QSETTINGS_POSTFIX` environment variable can be used to temporarily use a different QSetting file which is useful for different profiles or testing purposes.
 
 If you ever have the need to flush these, you can find the install locations as described in the [QT documentation](https://doc.qt.io/qt-6/qsettings.html#platform-specific-notes).
 

docs/guide/troubleshooting.md

@@ -203,6 +203,7 @@ The following environment variables may be helpful when troubleshooting issues:
 | --- | --- | ----------- |
 | BN_LICENSE | File Contents (String) | This variable is useful for using Binary Ninja with a license passed from outside a docker image without storing the raw license file inside. [Must contain](https://github.com/Vector35/debugger/blob/dev/scripts/build.py#L195-L196) the full contents of the license file.  |
 | BN_USER_DIRECTORY | Path (String) | This variable overrides the [default user folder](https://docs.binary.ninja/guide/index.html#user-folder) path. |
+| BN_QSETTINGS_POSTFIX | Postfix (String) | This environment variable is treated as a string postfix that can be used to separate saved QSettings for testing purposes. |
 | BN_DISABLE_REPOSITORY_PLUGINS | Flag (True if exists) | This setting will only disable plugins installed via the plugin manager. |
 | BN_DISABLE_USER_PLUGINS | Flag (True if exists) | This environment variable will disable all plugins loaded from the [plugins user folder](https://docs.binary.ninja/guide/index.html#user-folder). |
 | BN_DISABLE_USER_SETTINGS | Flag (True if exists) | This flag will cause Binary Ninja to ignore any [`settings.json`](https://docs.binary.ninja/guide/settings.html).|