Documented PYTHONOPTIMIZE; by Marc Lemburg.
diff --git a/Modules/main.c b/Modules/main.c
index b4bece6..757aa77 100644
--- a/Modules/main.c
+++ b/Modules/main.c
@@ -68,7 +68,7 @@
-d : debug output from parser (also PYTHONDEBUG=x)\n\
-i : inspect interactively after running script, (also PYTHONINSPECT=x)\n\
and force prompts, even if stdin does not appear to be a terminal\n\
--O : optimize generated bytecode (a tad)\n\
+-O : optimize generated bytecode (a tad; also PYTHONOPTIMIZE=x)\n\
-S : don't imply 'import site' on initialization\n\
-t : issue warnings about inconsistent tab usage (-tt: issue errors)\n\
";