"Is the HTML spec not out-of-band information?" It isn't. The HTML spec isn't transferred every time a webpage is accessed, so it's not exactly information. Al

"Is the HTML spec not out-of-band information?" It isn't. The HTML spec isn't transferred every time a webpage is accessed, so it's not exactly information. Also not really helpful, it's like saying "english" is "out-of-band information" when reading a website written in english. "Out-of-band" has a very precise meaning here, it comes from the telecom term "out-of-band signaling". There's a wikipedia page: https://en.wikipedia.org/wiki/Out-of-band_data https://en.wikipedia.org/wiki/Out-of-band_data