https://wicg.github.io/import-maps/#parse-a-url-like-import-specifier
When I saw the term "import specifier", I thought it was referring to ImportSpecifier from ecma262
I also thought that maybe there's a typo in this spec and actually it should be "module specifier"?

But after a while, I think it's referring to the specifierKey of the imports specifier map in import map

So the term "import specifier" used here is a little bit confusing.