The plain style writes the document as is. That is, the data in the text node is printed without any processing. This style will not rewrite an xml document in the exact same way it was parsed.

It should be noted that a processing instruction gets written as:

<?target*

where * is a whitespace if the content has no newline. Otherwise * is the newline character. Also, since the attributes do not collect any of the spaces or newline characters, the plain style cannot rewrite a file in the same way it was parsed. That is, if the file was parsed from

<parent att1="val1"
        att2="val2">
    <child/>
</parent>

then this style will print

<parent att1="val1" att2="val2">
    <child/>
</parent>