This seems like a really internal bad to use for anyone outside of efl function. Shouldn't it be at least @protected? Or maybe even a private eo function like for example EFL_CANVAS_GROUP_ADD_OPS as an _EXTRA_OPS?
Current c# generator ignore setter and getter docs when there's also a property doc. I would move or remove the setter and getter docs.
Adding @protected is a good move to prevent unintended use by apps. I am not sure it is honoured by the c# generator, though.
Applications should use @.hint_size_max instead.