Function application_fields 

pub fn application_fields<'a>(
    name: &'a str,
    package_id: &'a str,
    category: Option<&'a str>,
) -> [(&'a str, FieldWeight); 4]

An app’s searchable fields: its name, the words it is known by and what kind of app it is. The package id in full, or its last segment, identifies exactly one app and weighs as its name — hex-editor typed for so.tilo.hex-editor is the app’s identity and must outrank an incidental substring. Category ranks below the id because it’s a bucket, not an identity, but is still a name for the app (“office” is Notes). Prose an app says of itself — a tagline, a description, what it runs on — is not: a person typing a word has it in mind, and an app’s blurb holds most words at once.