Function store_from_elsewhere_at 

fn store_from_elsewhere_at(
    root: &Path,
    cert: Cert,
    address: &str,
) -> Option<KeySummary>

Keeps a key that came from elsewhere for address (a lookup: its domain’s Web Key Directory, keys.openpgp.org): its user IDs for that address alone. One of yours brought again so is merged without anything it names: only what your own primary key binds (a renewal’s signatures, a subkey), never another source’s user IDs into your certificate (review of 19 October 2026, F1).