It does, if you count the changelog of Bernd (Tibber [OH5] - Add-on Marketplace / Bundles - openHAB Community) and if you have a look at the sources, the resolution is QUARTER_HOURLY for the GraphQL API.
But, as I’m digging a bit deeper indeed I’ll find this JAR in my /userdata/marketplace/bundles/: 164158/org.openhab.binding.tibber-4.3.8-SNAPSHOT-Hourly.jar, which has the suffix “Hourly”.
Perhaps @weymann, was there something missing? I just removed and re-installed the [OH5]-version from the marketplace in my test-docker and this was the jar I got? Did the commit for opt-in QUATER_HOURLY make it in the marketplace binding?