blackbox-rs is a series of Rust crates that is to be paired with BlackBox, which allows you to create Bukkit compatible plugins using compiled langauges such as Rust.
Four of the crates are frozen at 0.4.0 due to no longer needing updates. The only one that gets updates is blackboxmc-rs-bukkit, which uses semantic versioning but places the patch version at the equivalant Minecraft version. For example, 1.2.21 is version 1.2 of the plugin, with compatibility for 1.21.
Due to the massive scale of Spigot's API, BlackBox is automatically generated by the generate.py script. There is a system for hand written code to be added via the additions folder. I am adverse to using macros or anything that would have the code generated at compile time, because I am a believer that if you are debugging a library, you should be able to go to the repo and have a good idea of what the code is doing.
A spigot.json file is required; it is not in the repo, you have to generate it via this repo.