Unlike recipes and loot tables, there's no option to choose a registry name for advancements. The "Edit mod element ID" button also doesn't work.
Issue comments
I have tried making a new recipe and specifying underscore in the name and underscore was in JSON too. Are there any specific steps to replicate this?
For advancements, we did not see a reason to add this as we do not plan to add overriding advancements option yet, but might consider it down the road.
About recipes, it seems to affect only 1.12.2 workspaces: the json uses the element name instead of the recipe registry name. I made another recipe in a 1.14 workspace and it worked as intended. Haven't tested the resource pack generator yet, but I guess it works fine.
About the advancements, I asked mostly because of readability, but overriding advancements also seems like a good feature!
I found another kinda related issue: when setting the id for recipes, snake case is ignored. All _ characters are removed from the json file name.
