[buro9]

I like that.

And if you were to add your domain to the public suffix list (https://publicsuffix.org/) it would effectively be treated like a domain name rather than subdomain name within browsers for JS security, etc.

For example, if you look at the list: https://publicsuffix.org/list/public_suffix_list.dat

You'll notice that myshopify.com is on there... effectively allowing subdomains of that (customer specific, each customer does not trust other customers) is now treated like a domain so that customer1.myshopify.com and customer2.myshopify.com are both isolated from each other by apps and systems that utilise the PSL (all major browsers, etc).

[kps]

Why is this a centralized list instead of just a DNS TXT record?

[fxtentacle]

Because Shopify might prefer to NOT be on that list, to make cross-vendor analytics easier for them.