Hmyea that’s something which was already suggested in https://forum.yunohost.org/t/yunohost-et-e/8787and we did not really continue the discussion because I guess we were too busy with many things …
I still don’t know much about /e/ … my understanding is that it’s a smartphone OS that is able to connect to a cloud of services managed by the /e/ people but there’s a strong wish that you should be able to self host all these services ? And that’s apparently what https://gitlab.e.foundation/e/infra/ecloud-selfhosting helps doing ?
With that said it’s really not clear to me if this is really something that is packageable to YunoHost : it sounds way too “meta” ? I mean this in the sense that it sounds like the repository is not about setting one specific web app, but more about setting up a whole bunch of services including a mail stack for example.
So I really doubt that you can have this as a Yunohost app, because it looks very much like it is itself an ecosystem, and you can’t have two very different ecosystem on the same machine … (even though the software are probably very similar, still, they are probably configured differently)
What I think would make more sense is to make Yunohost compatible with /e/, or viceversa make /e/ compatible with a Yunohost server … I have no idea what it implies though. But that would make perfect sense as we’re regularly thinking about how it’s annoying to install and configure every smartphone apps by hand, and how instead an integration between personal servers with smartphones would really contribute in adding meaningfulness and smoothness to the whole degooglization process to the general public !
In fact, I’m really afraid that this ecloud-selfhosting repository is just reinventing the same wheel as YunoHost, FreedomBox, Sandstorm, Cloudron and other friendly self-hosting distributions … But I don’t know if the /e/ folks realize how time consuming it’s going to be on the long-term to manage the various pieces of config, maintaining/upgrading them and the base system (Debian in our case), app packaging (and upgrades!), DNS configuration and port forwarding tutorials, the mail stack nightmare, security considerations, diagnosis, and making sure that all this is as easy as it can be for the end user (and certainly YunoHost itself is still only easy for tech-savvy folks…).
I don’t know how much thinking went into this self-hosted /e/ cloud or what its true goal is, but imho it’s either going to remain something that only only a few nerds-with-a-lot-of-free-time-and-energy will be able to setup and effectively maintain in the long term, - or - if they truly want to build a user-friendly self-hosting solution (and my understanding is that it’s not the priority of /e/ but I might be mistaking or it could evolve) they are going to have to invest several people full-time on it.
Instead, it would be really nice to see them choose an existing self-hosting project and trying to create compatibility with it… Of course here we’re on YunoHost forum, but any solution they choose among YunoHost, Freedombox or Sandstorm or whatever would make more sense in the long term than reinventing this wheel themselves… Though I do understand that in the short-run, writing your very own stack means having quick control over all the tiny details and therefore allow to quickly make progress.
Anyways … With that said, personally I’m already way too busy with everything going on in YunoHost itself and other related projects. But there’s really something meaningful to work on here if anybody is interested … Like “filling the gap between /e/ and YunoHost” … installing a Yunohost, installing a smartphone with /e/, and trying to see if and how you can connect pieces of one to the other, or what it would take to make it work. I guess if we had a list specific details to implement in YunoHost to make it compatible with /e/ we could work on it as long as it’s compatible with the philosophy of the project 
.
Sorry for the wall of text 