There are some preferences stored in com.apple.Accessibility that are required to be read and updated on macOS <rdar://problem/78752387>
Created attachment 430325 [details] patch`
Created attachment 430369 [details] Patch
Created attachment 430373 [details] Patch
Comment on attachment 430373 [details] Patch R=me.
Committed r278412 (238437@main): <https://commits.webkit.org/238437@main> All reviewed patches have been landed. Closing bug and clearing flags on attachment 430373 [details].