It's my favorite, too!

My favorite is the JSON syntax diagram https://www.json.org/json-en.html

Because design patterns, basically. I designed this page and have never seen codio.com before so I'd say it's just a reflection of common design paradigms for marketing pages.

Because a large number of sites use Bootstrap, Materialize, or one of a small set of base themesets.

Those "company" should try Shanghai's car plate lottery system as well :P

Kidnappers no long need to buy tons of magazines to compose an anonymous letter :P

This is awesome, but I like https://regex101.com/ more

I like ZANO more actually :)