This post is about the "Adaptive Conversations" in the game. The player could already examine certain objects, but now they can be joined by the characters in the game!
Click 'Read more' to read more about this mechanic.
Code-wise, this is just spawning a character, and based on the character spawned, a different conversation is played. The game looks at the character who's second in your party, unless it's Viola, in which case it looks at the first character in your party.
Games that have this sort of "banter" system usually make it a random endeavor as to which character will make the witty observation. I dislike this randomness: if you want a certain character to talk about it because that one's your favorite, you should be able to. Similarly, people shouldn't have to look on YouTube to enjoy all of your story content. The player can view all stories one by one if they choose by simply changing up their party.