The goal of this change is not to entirely support Big Sur, simply to add the named version.
<rdar://problem/64663032>
Created attachment 402592 [details] Patch
Everything looks good to me, but you will need someone else to do the act of r+. ¯\_(ツ)_/¯
Committed r263431: <https://trac.webkit.org/changeset/263431> All reviewed patches have been landed. Closing bug and clearing flags on attachment 402592 [details].