I’m not sure what you’re looking for… but will take a stab at two readings of it.
There’s an assumption there that we want an index. Baring in mind this is for everyone, perhaps some will not want their content on all indexes… power to the user, rather than any indexing interest.
You might have seen there are lists of websites http://dir.yvette.safenet being a simple one that I put up as memory of those website declares and that have PublicIDs that are easily guessed. Subdomains I find equally are guessed from common names and domains.
From what I’ve seen there is no route to automatic indexes or quering the DNS and I think that goes to the heart of the way the network is routed in privacy. Power is with those who use it; and so the choice of whether to make apparent a public service is with the host. If you craft a PublicID with a random bitcoin like address, there’s little chance of those not told of it ever seeing it.
Following from your example then there are limited basic approaches: email tuto might have PublicID tuto and then tuto.safenet which if it wants to be most accessible will have an index at www.tuto.safenet but some choose other common ones like home.tuto.safenet blog.tuto.safenet but it they put ery8ryerwrewr-wr3.tuto.safenet and tell noone then it’s as good as private. To be seen later what other limits on access might be put in place. If private data is made accessible to many or some password access to sites is enabled, then it’ll become doubly hard to know what is out there that isn’t advertised.
If you’re talking of playing host to content of many users and making an index of that available, then that is likely simpler but the dynamic element of what is possible is still to be resolved; obviously you could create a application that posts updates to a static list of those users content… but that’s getting beyond my abilities to describe.
Perhaps also consider asking over on the developers forum https://forum.safedev.org/