This lets you attach a 32 bit netMask to the field, so that when it is changed, it automatically flags the associated bitmasks on the netobject as dirty.
This is to shortcut having to flag certain masks being marked as dirty through protected fields and just simplify/streamline the code.
Unlike the regular Inspector, which requires a specific object or objects, from which the fields are pulled from, this lets you manually create fields, which can tie into any given object and their fields, global vars, and also not only supports the engine types for fields, but also triggers a callback to script if a field type is not found allowing fully custom fields to be handled as needed.