The author confuses ANSI escape codes and terminal escape codes in general. Because of this they declare that ANSI escape codes aren't standardized which is a bit silly. They were standardized in the ANSI X3.64 standard which is why they are called ANSI escape codes. ANSI X3.64 isn't even referenced in the article. ANSI X3.64 was withdrawn in favor of ISO 6429 which also isn't referenced in the article. ISO 6429 is based upon ECMA-48 which is referenced in the article. The article then references documentation for several other terminal escape code sets which are not part of the ANSI escape code set but the author positions as part of the non-standardized world of ANSI escape codes rather than being part of the ecosystem of terminal escape codes in general.