I just love file and protocol formats, it's one of the thing I'm fascinated by, maybe because it's a thing I deal with a lot professionally.

Recently I've been spending a lot of time with the JPEG format, I'll be posting an article about this on my blog soon (here now. Especially when it concerns thinking about formats like we think about physical matter, its composition, and fluidity.
I'm interested in how resilient the format is, if it has ECC or error detection mechanism, if small nudges can break it, if it has a compression mechanism, if it contains metadata, and more.

Personally, I think the novelty lies in how to represent the same content but more efficiently. For video, audio, and images, it's all about removing or joining information that us human can't always discern. I'm impressed by the likes of webp, avif, and others. All stemming from websites wanting to fight the web obesity while still keeping ton of pictures and videos.