Because it is XML some symbols should be converted to entity (even inside attributes):

Original Escaped
< &lt;
> &gt;
& &amp;

If you want to use some where (not everywhere allowed) line breaks or tabs you can represent them as following:

Original Escaped
Any kind of line breaks (\r\n, \n\r, \r, \n) \n - all line breaks use dos style at the end (\r\n)
Tab character (0x09) \t
\n combination \\n
\t combination \\t