https://github.com/BryceStevenWilley/DAYamlStructure/blob/526be711c5682c90b22e94793574e1402957ee62/da_yml_structure.py#L204-L205
I've tested and it can have comment and id at the very least. We could decide that it shouldn't, but those are things I'd probably find useful (maybe have already) in an include block.