Thank you for that. For elemental defs, you wrote:
" another container that requires you to copy all the contents of the files if you wish to mod a single one. Most tags in this file should be treated like a top-level node. "
I understand the first sentence well enough: it seems to be saying that if you want to mod elemental defs, copy the entire file (or modify it in place), however the second sentence says that the tag can be a "top-level node." What did you mean by this last?