Czech license plate: Dealer (documented since 2001)

Format, years and the law

Format: L99 999, for example H21 414 (L is any letter, 9 any digit)
The format above follows the issuing rules: a registration that fits it is one this series could have issued.
Years issued: Documented since 2001; the format is likely older than the first year documented. Still issued.
Vehicle class: Dealer: trade/garage plates bound to a business, not a vehicle. Issued for car, van, truck, bus, motorcycle, trailer, and machine.
Colours: Characters #009933 Background #FFFFFF
Size: 520 × 110 mm · every country's size

Dealer 280×200 mm

dealer · 280 × 200 mm

Dealer 200×160 mm

dealer · 200 × 160 mm
Who the plate belongs to: § 21 odst. 1 vyhlášky 243/2001 Sb.: the plates are issued "osobě, která zabezpečuje jízdy vozidel dosud neregistrovaných", manufacturers, importers and dealers moving unregistered vehicles. § 21 odst. 2 forbids their use on a vehicle already in the register, with one express exception: test drives during repairs, where the special plate is placed OVER the vehicle's own plate.

The series id is cz-dealer. The API returns its format, validation, colours and designs with the rest of Czechia's series:

curl -s https://vehiclesdb.com/api/v1/plates/cz \
  -H "Authorization: Bearer $VEHICLESDB_API_KEY" \
  | jq '.series[] | select(.id == "cz-dealer")'