What are all the different icons for?

Well each one has different types of lore/things you can look at that will reward a player for not only playing through the game, but also going deeper and really digging through it too! As you can tell, there's five different sections you can go too.

The first is animatronics and has in-universe descriptions for all of them just for more background on the characters you meet/unlock throughout the nights

The second is anything text related. Whether it's a newspaper article, sticky-note, or company email! While I do want to ability to see some of these in the office gameplay I know there needs to set aside time to be able to read them in full

The third is pictures, maybe there's a concerned employee taking screenshots of the animatronics acting up or weird moments? Could even serve as a logbook for Joseph to gather his thoughts about the nights and what he's thinking in the moment?

The fourth are audio files. Possibilities of hearing an old recording from a restaurant before this one! How about a call between two investors discussing the concerning practices of the business?

Finally the fifth one is more of what you'd expect in an extras menu, here you can see things like behind the scenes and previous ideas/versions of the game and it's characters. You will also be able to find the custom night in this part. Unless you haven't gotten any items to unlock the other parts, the final one will be the only one to stay lock until completion of the game.