Another weird case: In Google's server-side JS environment Apps Script, function names that end with _ are treated as private functions that cannot be called directly by the user or enumerated.
In the Python world I was in, trailing underscores is used to work around the ban on reserved words. The language grabs some of the best names for itself!
So a variable that really ought to be named `class` you name `class_`.
So a variable that really ought to be named `class` you name `class_`.