Display names for the external ids a matcher references, keyed by id.
An id absent from the map has no name to show — the row was purged, the
nickname column is null, or (for a hand-edited matcher) nothing was ever
there. Callers render the id, which is what the matcher actually stores.
Display names for the external ids a matcher references, keyed by id.
An id absent from the map has no name to show — the row was purged, the nickname column is null, or (for a hand-edited matcher) nothing was ever there. Callers render the id, which is what the matcher actually stores.