Bingo. Then you have IPNS, which uses a public/private key system to broadcast updates to a mutable hash value. So you can take the IPNS public key for so-and-s

Bingo. Then you have IPNS, which uses a public/private key system to broadcast updates to a mutable hash value. So you can take the IPNS public key for so-and-so's Wikipedia mirror, query the network for the latest hash signed by the corresponding private key, and use that hash to fetch content from IPFS.