Hi, folks.
I get the "a mod doesn't support extended biome IDs" when mousing over areas of the fullscreen map on JourneyMap. This does not happen over the entire map, but it does happen where I am currently standing, which is a vanilla biome. It also does not happen to the biome display under the minimap.
Sadly, journeymap seems to be a closed-source mod. They do have a support Discord (https://journeymap.info/Support), but I suspect it'd be far more useful for a jeid developer to talk with them then me.
Thank you.