HtmlGlobals.Pas (ThtString)
HtmlBuffer.pas (TBuffString)
Depending on the compiler switch UNICODE ThtString is set to an available unicode string type.
If UNICODE is defined it is set to string otherwize to WideString.
Type ThtString is the string type uses in HtmlViewer code.
Type TBuffString is an alias for ThtString and is used in HtmlBuffer.pas.