BNF (formal abstract systems) is baked into the structure of the Internet. Knuth himself suggested BNF be referred to as "Backus–Naur Form" in '64. [1]

Reference

[0] For example RFC5511: "Routing Backus-Naur Form (RBNF): A Syntax Used to Form Encoding Rules in Various Routing Protocol Specifications" https://tools.ietf.org/html/rfc5511

[1] "backus normal form vs. Backus Naur form" http://dl.acm.org/citation.cfm?doid=355588.365140