I often read and heard about burning tokens that were not sold when the ICO project was finished, I also knew that by burning the rest of the token was a strategy so the price of the token didn't fall, but if the DEV and the team didn't burn it was a crime? is there a requirement that the remaining unsold tokens must be burned?
there are no official rules or statements about it. there are even tokens that are not burned forever after the ico is finished and the team will only say "the project failed" so that there will never be a burning token.