That sounds interesting. But how can you test these internal binary formats? Do I need to extract that somehow?

ImHex will tell you if it's compressed. Do you understand data structures? Floats, all those data types?

I'd suggest looking at a format like msgpack to see what a binary data format could look like: https://msgpack.org/

Then be aware that proprietary formats are going to be a lot more complicated. Or maybe it's just zipped up json data, only way to tell is to start poking around at it.