The sxml-tools from the SSAX project at Sourceforge.
Oleg Kiselyov, Kirill Lisovsky, Dmitry Lizorkin. Port by Zbigniew
This egg provides most of the sxml-tools available in the SSAX/SXML Sourceforge project. It incorporates several different extensions:
Much documentation is available at Lisovsky's XML page and the SSAX homepage. For serious use, you will probably want to untar the egg and study the source and the included tests. See the README.txt file in the egg for details.
xlink, xlink-parser, fragments and guides are not provided as extensions, but they are included in the egg as source.
Although these files are pretty interdependent, they could be broken down further into separate extensions. sxpath could be pulled out, for example, with the caveat that txpath parsing would result in an error.
Not everything is tested, since tests are not provided for all functionality.
Examples are available in the sxml-tools documentation (see above). This one is a straightforward example of SXPath. Additionally, the sxml-tools tests are included in the egg. Untar it and read the README.txt file for details.
The sxml-tools are in the public domain.