Is it a correct, quick starting point to read the actual plaintexts that DTDs contain like the following, for a human-readable reference of all valid tags and properties for each specific DOCTYPE?
DTD for XHTML 1.0 Transitional
It seems to me that it becomes sort of a down-to-earth reference by doing so, but does it tell me "at run time" everything that is valid for a DOCTYPE, and as well to the browser program?
After that, what is a better reference? Where are the actual DOCTYPE standards, or are they the same as the general HTML standards? DOM level standards? W3Schools? Some other manual like "The HTML Reference Library 4.0" but for "newer" DOCTYPEs/HTML?