It can be both, because the definition of blithe is “showing a casual and cheerful indifference considered to be callous or improper.” And that is negative, but the other definition is “happy or joyous.” Which is positive.
Well if its a "real word" may depend on dialect, or where your from specifically. There are many words in Texas not really recognized as "real words" like "y'all" or many things like that. Perhaps it is a word somewhere. But I have never heard it. Remember, language is like a liquid, always shifting, and changing.
Answer:
They are adding new things.
It is just an update.
So expect it to be closed for a while.
