Hi, I'm an ops person.
I've been a developer.
Done distributed systems and System Engineering.
I did things with Haskell, Rust, C, Perl, Shell (lots of shell), GNU/Linux, {Free,Open}BSD, TLS, x509 and whatnot.

It's been some time since I started and sometimes I lose track of what I – hey, there's Python, JS, HTML/CSS missing in that list above – actually learned over the years.
There's still moments when I notice that I actually know what a TIME_WAIT on Linux is and why it's there and also what the difference between an abstract class and an interface is in Java.

So now my final question: Do you, if yes, how do you keep track of all that?

Note: I know that there are certain advantages to not keeping track (e.g. not accidentally claiming to know tech when your knowledge is hopelessly out of date).