Supporting multiple domains

[mrchrisadams]

Websites rely on content from multiple domains. How do we handle this?

We could do something like:

6 out 8 domains run on green power on this site.

[npdoty]

One approach would be to leave this sort of calculation up to the client. A domain's carbon.txt can report on the electricity and carbon source of resources hosted on that domain.

Web pages on that domain will frequently point to resources hosted on other domains, and very frequently that list will be unknown or hard to keep up to date, but a client that wants to know about the carbon impact of those additional resources can check the /.well-known/carbon.txt of each of those domains in turn. A browser plugin that wants to tell the user whether browsing a site is only using certified renewable energy would need to check each domain's carbon.txt when resources are loaded from other domains, rather than relying on a (likely incomplete or out of date) single conclusion from the top-level host.