You're right that an application project (a `binary crate` in Rust parlance) for embedded firmware versus a PC application is very different. But library crates

You're right that an application project (a `binary crate` in Rust parlance) for embedded firmware versus a PC application is very different. But library crates are often usable in both an embedded or system-level context or in a full-fledged desktop GUI application. Consider these common libraries you might use in either a `std` project (PC application, web microservice) or `no_std` project (embedded microcontroller firmware, bootloader, Linux kernel module, blockchain smart contract): - data encoding (https://crates.io/crates/base64 https://crates.io/crates/base64 for instance), - hashing (SHA2 https://github.com/RustCrypto/hashes/tree/master/sha2 https://github.com/RustCrypto/hashes/tree/master/sha2), - data structures (https://github.com/Lokathor/tinyvec https://github.com/Lokathor/tinyvec) - time/date manipulation (https://docs.rs/chrono/latest/chrono/ https://docs.rs/chrono/latest/chrono/)