Others have mentioned that include_str! is a macro, which I suppose it is. But if you look at the source it says that it is a compiler built-in[0]. If you dig into that, you'll see that it happens inside the compiler[1] (well duh). I feel that that makes it slightly different than a normal macro in that it doesn't expand to a bunch of Rust code. I found that pretty neat.

[0] - https://github.com/rust-lang/rust/blob/master/src/libcore/ma... [1] - https://github.com/rust-lang/rust/blob/e8af0f4c1f121263e55da...