About Question com.enthuware.ets.scwcd.v5.2.189 :

[ETS User]

wow, are you sure, about the yes and no, besides true and false?

[admin]

Yes, this is as per the specification.

[bluster]

I searched in the spec. Page 1-126 (5.16) came with up with hits in 3 paragraphs:

The omit-xml-declaration property is of type String and the valid values are “yes”, “no”, “true” and “false”. The name, values and semantics mimic that of the xsl:output element in the XSLT specification: if a value of “yes” or “true” is given, the container will not add an XML declaration; if a value of “no” or “false” is given, the container will add an XML declaration.
The default value for a JSP document that has a jsp:root element is “yes”. The default value for JSP documents without a jsp:root element is “no”.
The default value for a tag file in XML syntax is always “yes”. If the value is “false” or “no” the tag file will emit an XML declaration as its first content.

Another hit in page 129 (5.15) repeats the point of the first paragraph quoted above for omit-xml-declaration.

The quotes above are not quite the same as a blanket endorsement for all boolean variables to have "yes" and "no" for valid replacements to "true" and "false". If someone is aware of a more definite quote it would be useful to post it here.Thanks!