WebAccessibilityObjectWrapperMac.mm has a long comment about accessibilityShouldUseUniqueId that is next to accessibilityIsIgnored, not accessibilityShouldUseUniqueId.
<rdar://problem/86503027>
Created attachment 447195 [details] Patch
Created attachment 447233 [details] Patch
Committed r287104 (245293@main): <https://commits.webkit.org/245293@main> All reviewed patches have been landed. Closing bug and clearing flags on attachment 447233 [details].