What's in import.meta?
If you look at the import.meta docs on MDN you'll notice that it says:
The spec doesn't specify any properties to be defined on it, but hosts usually implement the following properties: [url, resolve]
So what is actually in there? MDN is correct in saying url and resolve are usually (always) implemented, but each run-time also sticks some other stuff in there. From my own testing, below are the values that exist for each major runtime.