Its always weird when people jump from "I don't understand something" to "no one understands something, they must have made it up" without any effort to verify that its not just you. Like is it arrogance?
You can clearly find the term almost immediately defined here for example https://bfy.tw/TOgI
You've hidden a LMGTFY link behind a URL shortener. Please don't do this, there are better (and gentler, kinder) ways to get your point across other than tricking people other than the parent poster into clicking the link.
You can clearly find the term almost immediately defined here for example https://bfy.tw/TOgI
Like any basic search will do so.