Options not documented in ROOT

To quote from an earlier post from 4 years ago

“I have found it systematically difficult to determine what options to use for any given function.”

Many methods in ROOT have option as an argument. What the allowed values are, and what they do does not appear to be documented any where.

Could this be fixed please?

We are working on documentation improvements (functions API).
Do you have a set of missing documentation that prevents you to understand the interface?