Function feature_cell 

fn feature_cell(entry: &Export) -> Result<String, Error>

How a table cell says which feature gates an entry.

Errors

Error::Unclassifiable for a #[cfg] that is not a single feature = "…" — an all(…), a target_os, a not(…). Publishing such an entry as “always” would be inventing an availability the code does not promise, and the right answer is a documentation decision rather than a guess.