Then you open a tab, or a new browser, and go to
https://ipfs.io/ipfs/QmWPvCEnSkGR8iTs6uiZSNkbupbv7sz3MV5mKW3erHYVZa/world/z1
And … magic ! The answer is coming back in your console …
A ressource is “downloadedable” by js-ipfs only if a “true” node have already seen it.