A discussion was brought up about HTML's omittable tags, which led me to wonder what the first thing is different webmasters write when writing a webpage, if any.
When I write a new webpage, the first thing I write is
<!doctype html><html lang=en><meta charset=utf-8>. (The
en would change if I wrote a page in a language other than English, but usually I write in English.)
Some webmasters may have
<head></head><body></body></html> but I tend not to write those since they're completely omittable.