The few bad/worse developers are then 10% and would have to be really bad

This is part of the joke. It can be true but it's almost impossible to have this kind of distribution among developers.

> It can happen that 90% of programmers literally better than the average.

While mathematically true, in practice almost impossible

Anecdotally my experience is that for every one really good developer there's about 25 or 30 mediocre ones, and 5 or so really terrible ones. This is based mostly around what I've seen conducting interviews in my area. That is also highly variable, I did some interviews for another office (in another country) and saw ratios more like for every three good developers there were two mediocre ones, and no terrible ones. Maybe we just had a much better recruiter feeding us candidates in the other country, or maybe they just have exceptional programmers living there.

Just symmetrically distributed, doesn't have to be Gaussian. I will crawl back into my hole of pedantry now.

10000 lines might not be enough. I'm not sure that it's possible to determine whether something is a valid email address other than trying to send mail to it. If you haven't read the RFCs, they're pretty much a nightmare. The HTML5 spec has this little gem:

> This requirement is a willful violation of RFC 5322, which defines a syntax for e-mail addresses that is simultaneously too strict (before the "@" character), too vague (after the "@" character), and too lax (allowing comments, whitespace characters, and quoted strings in manners unfamiliar to most users) to be of practical use here.[0]

[0] https://www.w3.org/TR/html5/forms.html#e-mail-state-(type=em...