At the beginning of the game, Frog Detective says something in
Indonesian
So I was wondering what those lines could mean.

I couldn't sleep or eat or do anything at all. This question was bothering me too much. So I did hours of intense research, asked an expert interpreter and even travelled to Indonesia, just to find the answer.
After years of sleepless nights, I finally found the truth.

It means exactly what Frog Detective says:
"Welcome back"