Cargo Features

[dependencies]
byondapi-sys = { version = "0.12.3", default-features = false, features = ["byond-515-1621", "byond-516-1651"] }
default = byond-516-1651

The byond-516-1651 feature is set by default whenever byondapi-sys is added without default-features = false somewhere in the dependency tree.

byond-515-1621
byond-516-1651 default

byondapi-sys has 3 features without comments.