manager key doc is not found 404

http://tezos.gitlab.io/mainnet/api/rpc.html#get-block-id-context-contracts-contract-id-manager-key i use a lot of time to find it but i found nothing

[Nic] I think the right link is http://tezos.gitlab.io/alpha/rpc.html#get-block-id-context-contracts-contract-id-manager-key.