The members of the Bundesrat (Länder ministers and plenipotentiaries),
projected to their factual fields (name, party, Land, membership flags).
The optional filter narrows the list by Land and/or party (see
filterMembers); an unknown key, a state that is not a Land or a blank
value rejects with a BundesratValidationError before any request.
The current plenary session with its agenda items (TOP numbers and their Drucksachen — the latter amtliche Werke under § 5 UrhG).
Committee appointments and dates (Termine), projected to their factual fields.