My guess actually is that iOS/Apple no longer uses this particular list. I found this by intercepting traffic on an older jailbroken iOS 13 device. Given how old some of the domains in the list are, I'd guess that iOS 15 no longer uses it. I also never actually saw my phone fetch this list, I just saw this URL in another configuration response.

tl;dr; I bet it'll never get updated. (but some similar list at a more hidden/protected location likely will be)

p.s. this list of common spelling corrections is interesting too: https://cdn.smoot.apple.com/static/static_corrections_dict/2...