Date, or date and time with a time zone offset. YYYY-MM-DD, or YYYY-MM when the day is not known. ISO 4217, three capital letters. Currency symbols are not accepted. ISO 3166-1 alpha-2 of a Housebook market. Always stated. We never infer the unit from the country. What the amount is for: the whole unit, a square metre, or a square foot. A live contact for questions about the data: email or phone. Missing kind is read as photo. One child element per locale, named by its two-letter code: en, ru, de. No phone numbers, no messenger handles, no links to other sites: this text goes onto a public page of ours. Must match the id of a building in the same file. Leave out for land and commercial units: zero would read as a studio.