Enhanced section on exported variables in the README

modules/gpg-agent/README.md

@@ -12,12 +12,14 @@ To enable SSH-Agent protocol emulation, add the following line to *zpreztorc*:
 
     zstyle ':prezto:module:gpg-agent' ssh-support 'yes'
 
-Variables
+Exported Variables
----------
+------------------
-
+
-Please note that if you use this agent, the variables will only be visible to
+Please note that if you use this agent, the variables it will create and 
-other instances of zsh. Should you use a non-shell mail user agent such as
+export (`GPG_AGENT_INFO`, `GPG_TTY`, and if you have `ssh-support` enabled, 
-thunderbird, make sure it inherits the variables. For an example how to
+also `SSH_AUTH_SOCK` and `SSH_AGENT_PID`) will only be visible to other 
+instances of zsh. Should you use a non-shell mail user agent such as 
+thunderbird, make sure it inherits the variables. For an example of how to 
 achieve this, have a look at issue #419 in the [issue tracker][2].
 
 Authors