The `nmu` boolean in the upload_history table is never set: 0 of 997,602
rows are TRUE, while 38,052 uploads in the same table carry NMU version
conventions in their version string (+nmuN or the non-maintainer
revision form -z.N, Dev-Ref 5.11.2). The upload_history_nmus view
aggregates this same always-FALSE column, so it reports no NMUs anywhere.

Tools that try to identify non-maintainer uploads via upload_history.nmu
therefore silently get zero results. We currently detect NMUs from the
version string instead.

Suggested resolution: either populate `nmu` (e.g. from the version-string
conventions above), or document the column as unmaintained/deprecated and
note the version-string approach so downstream users don't rely on it.

Reproduction (against the public mirror):
  SELECT count(*) FILTER (WHERE nmu),
         count(*) FILTER (WHERE version ~ '\+nmu[0-9]+$'
                             OR version ~ '-[0-9]+\.[0-9]+$')
  FROM upload_history;