I need to know these things, people. Contrary to persistent rumor and all available evidence, I am not in point of fact an expert on everything.
*Short version: it’s the bit in a law where it’s noted that declaring one part of the law unconstitutional doesn’t make the rest of the law unconstitutional, either. Standard practice to put that in there, these days…
…but then, nothing about Obamacare was standard practice.