Not sure what you mean, but to expand on what I wrote, JSR rewrites the import statements to include file extensions and full version numbers for package dependencies, so that the imports can be resolved without looking for them in multiple places.
There's a way to download JSR packages and use them with npm too. I don't know what it does in that case.
There's a way to download JSR packages and use them with npm too. I don't know what it does in that case.