I'm not a native English speaker, so I mostly learn English by books or internet. When we look up Collins English Dictionary about the meaning of "Editorial" :
"An editorial is an article in a newspaper which gives the opinion of the editor or owner on a topic or item of news."
That's something we call as "사설" in Korean. In Korea, people write editorial about our recent president impeachment, thoughts on foreign policies, or the Chinese food restaurant nearby their office. If someone uses that phrase to describe solutions, it will be really awkward.
In Codeforces, when we say "Editorial" it mostly means "Solution" — that is, mathematical facts. So, according to dictionary, this post is more likely to be called as "Editorial" than the usual one we know.
Then, why does CP community uses the word "Editorial" for referring solution? Does it have some other meaning related to "solution"? If not, is there some history for using that phrase?