There is KASM VNC, which easily allows to run whole Desktops or single Applications through your Web browser.
I think they use NoVNC or something. There is support for single Wayland applications, but I dont know currently how good it is and its a bit bloated for this specific use case.
Idea: Firefox and Thunderbird use Web Technology to display, dont they? The Browser is completely configurable with CSS. If there is something missing please add.
So you wouldnt need a traditional system and an X server / wayland compositor, but your browser could handle the compositing?
You would then need additional stuff
- shared storage for downloads
- redirecting local downloads to your browser, like KASM does it
- login interface to access the “website”
- some form of multi-user access, not sure if this is supported at all.
Why? Office 365 has this with Outlook, and Outlook is nowadays a Webapp afaik, just running locally.
It is useful to access
- a secure browser
- a configured mail app with many accounts, good interface, calendar, contacts, PGP, etc.
- you can use thunderbird from Tablets
- You can have an isolated Browser
This may be duplicating KASMs effords, but I think it may be really cool and better for these two apps, IF they actually use Web technology only.
I believe your best bet is to setup linux on some computer / server / VM and access the thing remotely from a browser. That can be gone with solutions such as Guacamole (…manual setup…) OR linuxserver/webtop that is an abstraction over Guacamole to make it more easier to setup. With that running you can access the remote machine from any browser and use those applications.