to be clear, if the block you're defining doesn't exist it'll be custom and not obsolete, but if you define a block that does exist, then that block will be of that category.

here's a problem though, because what happens if you try to use that block? it would use the official one, right? which would force you to break out " :: custom " at some point. but i still feel like this bug should be fixed as 3.0 never renders the way that picture does