Hi @Clipping, welcome — it is legit, but it is not a current extension.
That’s an old page from when there was an Evernote extension that worked, I should take it down.
The extension used an AppleScript to add the new note to Evernote, but with Evernote 10 the AppleScript support was removed from Evernote which broke the extension. So I took it down from the list.
However I’m hoping to put together a new extension using the Evernote API soon.