When they say "pure HTML" they mean, that they access the HTML api directly. The non pure HTML examples use third party javascript libraries as an layer between the html api and their own javascript code.
"According to TKG Section 113 (German Telecommunications Law), the public prosecutor and the police can access the user data held by telecommunications providers such as ourselves relatively easily. A simple information request suffices; no court order is needed. According to TKG Section 113, a telecommunications provider has no legal recourse against such a request; it must comply. It should also be noted that according to TKG Section 113 (II), the provider is required to treat such a request confidentially, and that the affected customer must not be informed about the request."