Cargo Features

extism-manifest has no features set by default.

[dependencies]
extism-manifest = { version = "1.9.0", features = ["json_schema"] }
json_schema = schemars

Features from optional dependencies

In crates that don't use the dep: syntax, optional dependencies automatically become Cargo features. These features may have been created by mistake, and this functionality may be removed in the future.

schemars json_schema?