I feel exactly the opposite, compared to Python at least. It's usually easy to find the definition of the structs, and then you can quickly make sense of what a given function can and cannot do, and what it as access to.

With Python I never know, since something might have dynamically added or changed some methods or fields along the way. I almost always end up sprinkling dir() all over just to figure out what exactly is going on.

I think that's because it's C, where you have to use void* occasionally, structs are often anonymous to avoid compile-time increases from including another header file, and there's a hellscape of pointers involved in doing anything significant. If you picked up a modern language with static typing, like Rust, Go, Kotlin, or even C++/Java, you might see some significant readability benefits.

Imagine how much worse those structs with pointers to structs would be without static typing though. This feels like a complaint against C, not a complaint against static types.

It is a comment about how large projects, at least from my experience, seem to use complex data structures that takes several indirection to follow.

In both C and python I have also see something akin to a mini language inside the large projects, where understanding the code becomes almost impossible without documentation. In C, both macros and pointers to structs with more pointers can do a lot of heavy lifting to hide every detail of how something is being done and just leave the intention. Great if one want to see a high level concept and creating new features, but terrible if you want to know where that one bit of information is being stored and how to inject your own code into the core parts of the project. Similar, large projects in python tend to use meta, monkey patching and other dark magic patterns to really hide the low level details while making it easy to create new features.