<tterrag> ok cpw, I've nailed it down. the issue is here: https://github.com/MinecraftForge/MinecraftForge/commit/f8cba13b5b3644396715830acde683780d96f0ad#diff-440348b2a38b6ade654eb82598d98084R68
<tterrag> by having it default to v2, this enforces uppercase lang files (vanilla legacy handling code)
<tterrag> I'm not sure what the solution is though
<tterrag> should mods just supply their own mcmeta?