“With ever-changing devices, browsers, operating systems, form factors, specifications, personal preferences, tooling, and corporate interests, the web is in a constant state of flux.”
Every one of these tags is a fossil of some company trying to own the web for a year. IE compatibility modes, Apple’s web-app flags, the mobile viewport hacks. They never got removed because nobody removes anything from a template. Your production site is still shipping the browser wars in its head element.