A Dutch postcode is four digits, a space and two letters — 1015 CJ. The pair of letters narrows it far enough that the postcode and the house number together identify a single address, which is why Dutch checkouts routinely ask for exactly those two fields and fill in the street and town themselves. An international form that demands a full street address from a Dutch customer is asking for information their own systems consider redundant.
The street line puts the name before the number, as in Germany, and house numbers frequently carry a suffix — a letter or a hyphenated addition for a subdivided building. Those suffixes are part of the address, and a numeric-only house-number field silently drops them.
This is one of four countries where this generator publishes the real geographic half of the postcode and generates the rest. A Dutch address here is pinned to one of 15 real cities and carries genuine four-digit codes for it, with the two letters invented — because those letters are precisely what would narrow the code to a real doorstep. The complete postcode is not verified as assigned or matched to the generated street. It may coincide with a real code; this is a test sample, not a checked delivery address.
Dutch names are the other reason to keep a Netherlands fixture. Measured over 20,000 draws from this generator's own Dutch pools, 43.7% of surnames contained a particle — van, de, van der — which means a whitespace-splitting name parser gets the family name wrong on nearly half of them. Dutch alphabetisation conventionally ignores the particle too, so a sort keyed on the raw string files half the country under V and D. If your product sorts or matches on surnames, the Netherlands is the cheapest place to find out.