Function prefix_diagnostics 

pub fn prefix_diagnostics(
    query: Query<'_, '_, (&Element, &Prefixes, &Source, &RopeC, &Label, &Wrapped<TextDocumentItem>, &DynLang), (Or<(Changed<Element>, Changed<Prefixes>)>, With<Open>)>,
    client: ResMut<'_, DiagnosticPublisher>,
    lovs: Query<'_, '_, &LocalPrefix>,
    prefix_cc: Query<'_, '_, &PrefixEntry>,
    config: Res<'_, ServerConfig>,
)

ECS system: runs prefix_diagnostic_helper for every open document whose triples or declared prefixes changed.

Skips languages that opt out via LangHelper::supports_prefix_diagnostics (e.g. JSON-LD, which pre-expands all terms before storing them as triples).