It's unofficial - the section was titled incorrectly, sorry about that! Holdover from when there was no set structure for Karaoke pages. It's been corrected now.
There's no specific source on it since multiple people have edited it since the page was made.
Thanks for the answer. It says it's a literal translation now but not meant to be singable, thing is though it really does seem singable. So I must say whoever did it did a great job!