Celebrating uncertainty as an essential part of life, this IDA plugin lets you uncertaintify (or, add trailing question marks to) the names of local variables in the pseudocode view.
Simply put the Python file in %APPDATA%\Hex-Rays\IDA Pro\plugins. Both Python 2 and 3 are supported.
In the plugin's source code, change the value of REGISTER_CONTEXT_MENU_ITEMS to False.
Without delving too deep into the philosophical niche of plugin existentialism, this plugin has been written because starting with version 7.5, Hex-Rays will complain if a local variable name is "not a valid C identifier", thus prohibiting names containing question marks.
Inspired by a friend's idea, Uncertaintifier amends this situation.