About the OPSEC Level 2 : Anonymity category

https://blog.nowhere.moe/opsec/anonymityexplained/index.html

Anonymity is the absence of Identification (or Onymity), it is when individuals are indistinguishable from each other, they all look the same.

DISCLAIMER: That Someone remains Anonymous UNTIL THEY MAKE ONE OPSEC MISTAKE !

Keep in mind that maintaining Anonymity is a much stricter practice than that of maintaining Privacy, as you will see, more threat vectors come into the picture.