There are a few variables on `DocumentSourceExtension` that are artifacts from the POC or earlier iterations of extensions. Having these variables causes some issues during expansion, as the expanding AST or parse node won't have the same member variables as the expanded parse node.

Because of this, constructing new `DocumentSourceExtension`s can prove to be difficult without this information.

This ticket should remove any DocumentSourceExtension variables that are not actually used or necessary for the class.