[csswg-drafts] [css-values] Double bar with duplicate values

litherum has just created a new issue for 
https://github.com/w3c/csswg-drafts:

== [css-values] Double bar with duplicate values ==
https://drafts.csswg.org/css-values-4/#comb-any states:

`A double bar (||) separates two or more options: one or more of them 
must occur, in any order.`

So, if you have the syntax `a || b` then the following constructions 
are valid:
```
a
b
a b
b a
```

Does the "them" in "one or more of them" refer to the values or 
instances of values? Or, more concretely, is the following valid:

```
a a b
```

The spec could be clearer on this point.

Please view or discuss this issue at 
https://github.com/w3c/csswg-drafts/issues/710 using your GitHub 
account