Which balance-sheet items belong in 'operating' working capital, and which do not?

Operating NWC covers the balance-sheet items of day-to-day business, not financing or capital-structure positions.

trade receivables, inventories, trade payables, other operating receivables/payables.

cash (a financing item), tax liabilities (often separate), debt (capital structure), accrued interest, pension provisions (net-debt-like).

family-owned companies often have large 'other assets' — check critically whether they are operating or a hidden investment.

right-of-use assets are NOT NWC but fixed assets.