See Bozo Detection for more details on the bozo bit.
|bozo may not be present. Some platforms, such as Mac OS X 10.2 and some versions of FreeBSD, do not include an XML parser in their Python distributions. Universal Feed Parser will still work on these platforms, but it will not be able to detect whether a feed is well-formed. However, it can detect whether a feed's character encoding is incorrectly declared. (This is done in Python, not by the XML parser.) See Character Encoding Detection for details.|