When we change this, we can just as well grep for `Array.prototype.slice.call`, so `[ES6-ARRAY_FROM]` comments do not add very much. (I actually vaguely think the other notes do not add very much either, because it's easy to fix things up as needed later as-needed, they aren't used very consistently, and we don't have a clear time plan on changing to them. An external (public or private) document on the state of things and what to grep for might add the same amount of value with less clutter. But it's up to you, my opinion on this isn't all that strong.)