The Tor Browser / file revision

 @echo off

 set "VIRTUAL_ENV=__VIRTUAL_ENV__"

 if defined _OLD_VIRTUAL_PROMPT (

     set "PROMPT=%_OLD_VIRTUAL_PROMPT%"

 ) else (

     if not defined PROMPT (

         set "PROMPT=$P$G"

     )

 	set "_OLD_VIRTUAL_PROMPT=%PROMPT%"	

 )

 set "PROMPT=__VIRTUAL_WINPROMPT__ %PROMPT%"

 if not defined _OLD_VIRTUAL_PYTHONHOME (

     set "_OLD_VIRTUAL_PYTHONHOME=%PYTHONHOME%"

 )

 set PYTHONHOME=

 if defined _OLD_VIRTUAL_PATH (

     set "PATH=%_OLD_VIRTUAL_PATH%"

 ) else (

     set "_OLD_VIRTUAL_PATH=%PATH%"

 )

 set "PATH=%VIRTUAL_ENV%\__BIN_NAME__;%PATH%"

 :END