Restore environment from parent for external processes

README.md

@@ -16,4 +16,20 @@ You would have to know the library version of the host system and decide whether
 application is started. This is exactly what the patched AppRun binary does.
 It will search for `usr/optional/libstdc++/libstdc++.so.6` and `usr/optional/libgcc_s/libgcc_s.so.1` inside the AppImage or AppDir.
 If found it will compare their internal versions with the ones found on the system and prepend their paths to `LD_LIBRARY_PATH` if necessary.
-You should also put `exec.so` into `usr/optional`.
+
+You should also put `exec.so` into `usr/optional`. This exec.so library is intended to restore the environment of the AppImage to its parent.
+This is done to avoid library clashing of bundled libraries with external processes. e.g when running the web browser
+
+The intended usage is as follows:
+
+1. This library is injected to the dynamic loader through LD_PRELOAD
+   automatically in AppRun **only** if `usr/optional/exec.so` exists: 
+   e.g `LD_PRELOAD=$APPDIR/usr/optional/exec.so My.AppImage`
+
+2. This library will intercept calls to new processes and will detect whether
+   those calls are for binaries within the AppImage bundle or external ones.
+
+3. In case it's an internal process, it will not change anything.
+   In case it's an external process, it will restore the environment of
+   the AppImage parent by reading `/proc/[pid]/environ`.
+   This is the conservative approach taken.