Function document_index_admissible_for_query 

pub fn document_index_admissible_for_query(
    index: &Index,
    resolved_time_ranges: &[ResolvedTimeRange],
    skip_bindings: &[SkipIfAbsentBinding<'_>],
) -> bool

index_admissible_for_query for a picker reading documents through the index’s entries: a summableOffCountIndex index keeps none (its source serves the documents it counts), so it never serves such a read.

Unversioned, so every protocol version reaches it (the document pickers of every lowering): only protocol version 14’s grammar admits a summableOffCountIndex index, so before it this is exactly index_admissible_for_query.