In bug 226515, wtf/Optional.h was included and this file no longer exists. There's also another one in.
<rdar://problem/79703249>
Created attachment 432123 [details] Patch
Downloading attrs-18.1.0... Installing attrs-18.1.0... Installed attrs-18.1.0! Downloading mechanize-0.4.5... Installing mechanize-0.4.5... Installed mechanize-0.4.5! Darin Adler on Slack found in /Volumes/Data/worker/Commit-Queue/build/Source/WebCore/ChangeLog does not appear to be a valid reviewer according to contributors.json. /Volumes/Data/worker/Commit-Queue/build/Source/WebCore/ChangeLog neither lists a valid reviewer nor contains the string "Unreviewed" or "Rubber stamp" (case insensitive).
Created attachment 432126 [details] Patch
Committed r279207 (239093@main): <https://commits.webkit.org/239093@main> All reviewed patches have been landed. Closing bug and clearing flags on attachment 432126 [details].