This is a simple example mailcap file. SGML is gaining acceptance as the standard interchange format for word processors. SGML provides facilities for higher-level text marking, which can mean font selection or language identification. SGML can be used to differentiate between Chinese characters and Japanese characters in a single text. Thus, SGML can be used to hide unification.
Unification is irrelevant to users who acquire software that properly meets their needs.
Weblint is a perl script created by Neil Bowers that checks HTML code. UniPress W3 Services created this WWW forms-based interface. Or you may simply supply a URL of a page anywhere on the World-Wide Web to be checked. Illegally nested elements. Hopefully, you will find this free service useful.