Definition of "collection" is nonsensical

https://w3c.github.io/webdriver/#dfn-collection

A collection is an Object that implements the Iterable interface, and whose:

• initial value of the toString own property is "Arguments"
• instance of Array
• instance of DOMTokenList
• ...

Problems:

• Expressions like "whose [...] instance of Array" are ungrammatical
• It's unclear whether all conditions of the list must hold, or a single one suffices
• Arguments objects do not have a toString own property. They inherit a toString property but its value isn't a string, it's a function.
  What this probably meant was Call(%Object.prototype.toString%, collection), but of course this would still consider ({[Symbol.toStringTag]: "Arguments"}) as an Arguments object even if that's not the case.

Start at the WebDriver specification's collection definition linked in the issue, then review the referenced definitions for Object, Iterable, initial value, own properties, Array, and DOMTokenList. Clarify the list's grammar and intended conditions, and verify the Arguments-object wording against the linked ECMAScript Call definition; done when the definition is precise and unambiguous.