It's not necessarily fun though, lol

For example, I would say that most devs hate to read the code of other people and reading code is like 90% what you do as a dev. So devs realized that maybe, code readability is way more important than writing something clever you won't even understand yourself anymore next week.

Now imagine that code is obfuscated. This means the code itself is written on purpose in such a way that it's hard to read. There are tools which strip all information from the code which isn't necessary to run it. And probably tools that add "dead code" that never gets run but just exists to confuse reverse engineers and more obfuscation techniques.

That's what reverse engineering is like, lol

Not every code is obfuscated but closed-source code usually is to prevent reverse engineering.

Would already be interesting to see if they obfuscated their code.