Feathers of the Zephyr Package no longer obtainable?

Hi! I just saw this backpack/glider combo and I liked it, so I decided to search how to get it in the wiki, but it says that it's not contained in any container. I thought I could choose it from the Black Lion Exclusives Chest, but in the wiki says otherwise. Does that mean that there isn't any way to get it or is just that the wiki is incomplete?

Yep, at this time it's unobtainable. It's likely to be added to the Exclusives Chest once it's inevitably re-introduced though. If I were a betting man, I'd wager on it being back in the Exclusives Chest come next Black Lion Chest "rotation".