Function fact_served 

pub fn fact_served(
    store_root: &str,
    category: &str,
    key: &str,
    value: &str,
) -> bool

Whether the fact category/key of the knowledge store of store_root may be delivered with value to the running request, and the one place a fact’s sources enter the call’s capture (archive::bindings::serve):

• a fact bound to sources at its write is re-authorized for the request’s project; false means it must be left out of the reply. Served, it publishes its files;
• a fact without a binding marks the capture incomplete and is delivered as before — the reply that carries it has no known lineage.

Without protection every fact is delivered and nothing is published. store_root is the project root as the store’s writer named it.