User blog comment:Rappy 4187/Technical Update: April 13, 2016/@comment-26408193-20160413201331/@comment-5065259-20160413204208

Discussion Moderators already can edit pages locked up to sysop, this is because staff merged the regular protect/unprotect permission with the editprotected permission. editprotected is what allows editing sysop locked items. As sactage and DEmerson said, the other groups don't need access.