So I'm not sure if this is a bug or not, but it'd be great to clarify this I think, because I looked around a fair bit about this (here on github, in MI discord, other MC discords), and often someone asks where iridium ore generates, why is there none, is it meant to exist, but there's never really a definitive answer that I could find.

Accidentally when checking worldgen related stuff, I found that in MI, under data/modern_industrialization, there's worldgen/configured_feature and worldgen/placed_feature entries for Iridium ore (a pair of deepslate_ore_generator_iridium.json and ore_generator_iridium.json in both), and the neoforge biome modifier for it is also set up in neoforge/biome_modifier/deepslate_ore_generator_iridium.json and ore_generator_iridium.json.

So the iridium ore feature is set to spawn in any overworld biomes, the feature is configured with replacement targets and spawn count + height range is all set. There's just one single variable that makes it not actually spawn, which is in the configured_feature pair, it's set to "size": 1,. When using minecraft:ore as a type for configured features, a size of 0/1/2 all result in 0 actual ores generated (vein size of max 0), it's only at size of 3 where it starts spawning (at which there's a max of 4 in a vein). It's the minecraft:scattered_ore type that allows a size of even just 1, in vanilla used by ancient debris.

So is it actually a typo and either the type is meant to be scattered ore with size 1, or just regular ore but size 3, so that it actually starts spawning but accidentally got lowered to 1 with the intention to make it more rare (and invertedly making it cease to exist), or is it not meant to exist and all these related files are just a placeholder? I also thought they might be present so a modpack author can easier adjust it as it's essentially a template ready to go, in case they want it to spawn in their pack, but I'm not sure there since it's probably not that out of the way to just create a custom feature set for the ore to generate if a pack author wants to.

I believe this is a bug. @Technici4n is Iridium meant to spawn in world? I think this has been a bug for a long time if it was originally intended to generate in-world.

In my opinion I think progression is just fine without it generating so I don't see a problem with choosing to leave it so that it does not generate. If that is what we choose to do, the tooltip for the Y levels it generates in definitely needs to be removed for it.

The original idea was that it would generate, but given the current progression I think it should indeed not.