Serde is a Rust library for serialization. serde_derive allows creating serialzers/deserializers automatically by marking structs. It uses Rust's procedural macros to generate code at compile time. Rust compiles procedural macros at compile time before compiling rest of code. To speed up compillation of code using serde_derive, a recent change was made to implement the procedural macros with a precompiled binary

serde is also used in a LOT of projects and pulled in as a dependency or subdependency often in the crates ecosystem.

For organizations with internal transparent reproducible build guidelines or similar rules, this maybe complicates things and introduces uncertainty.

So much uncertainty nowadays. It's exhausting.

You can take the generous / positive view that this will encourage formalizing reproducible build policies in organizations.

Water is wet, the sky is blue.