TBL might not have used SGML tools, but surely wanted to make HTML extend to SGML proper and appeals to SGML concepts at several places in the linked document:

TBL might not have used SGML tools, but surely wanted to make HTML extend to SGML proper and appeals to SGML concepts at several places in the linked document: > Currently HTML documents are transmitted without the normal SGML framing tags, but if these are included parsers will ignore them. > In SGML terms, paragraph elements are transmitted in minimised form > These tags are kept as defined in the CERN SGML guide. Their definition is completely historical, deriving from the AAP tag set. > (not good SGML)