Language and currency
The app speaks English and French, and prices in euros or US dollars.
Settings → Language offers System, English and Français. Settings → Currency switches every price between euros and US dollars.
Each venue quotes in its own currency: Cardmarket in euros, TCGplayer and PriceCharting in dollars. Zukan converts the figures into the currency you chose. A card quoted only in the other currency is shown converted on its sheet, but the collection total leaves it out and says so, rather than mixing two currencies into one figure.