Represents the plain text output format (MIME type "text/plain", name "plainText"). This format doesn't support
escaping. This format doesn't allow mixing in template output values of other output formats.
The main difference from
UndefinedOutputFormat is that this format doesn't allow inserting values of another
output format into itself (unless they can be converted to plain text), while
UndefinedOutputFormat would
just insert the foreign "markup" as is. Also, this format has {"text/plain"} MIME type, while
UndefinedOutputFormat has
null.