When I publish my mod using the publish gradle script that comes with the forge mdk and use the resulting .jar file in my Minecraft mods, none of the objects I've added are named with the strings I provided in en_US.json. They all use the resource location as the name. I tried providing an en_US.lang as well, but that didn't help. Whenever I ran the mod in development using the runClient script from the mdk, all the items were named correctly. Why is this happening and how can I fix it?

I got it to work. Strangely, naming the file en_us.json instead of en_US.json fixed it. It seems Minecraft cares about the casing.