The Leonida number plate

Ordinary traffic in the Extended Look carries the modern Leonida plate: the state name in a serif across the top, an orange sitting between the letter block and the number block, and SUNSHINE STATE along the bottom edge. Jason's red Sentinel convertible does not. Its plate reads HRP RB9 on a yellowed design with "19 Discover '78" across the top and GLORIANA underneath, which is the visual language of a period plate kept on an old car rather than a current registration.

Number plates are where Rockstar hides the boring, load-bearing worldbuilding: the state slogan, the era a car is from, and in previous games the counties a vehicle is registered in. Two designs in the same traffic means the game is tracking vehicle age in its props. What GLORIANA refers to has not been explained anywhere, and Rockstar has published nothing about plates.