it is not used. and not generated at docs of C# and python languages.
Just to be sure, for the future: When there are docs at the Property and the Accessor level (set or get) then the C# doc generator will only use one of them.
It is OK to have docs ONLY at the property level, or ONLY at the Accessor level.
I prefer to have docs only at the property level and split them into the setter and the getter only when these methods perform significantly different operations.