lxml is copyright Infrae and distributed under the BSD license (see
doc/licenses/BSD.txt), with the following exceptions:

Some code, such a selftest.py, selftest2.py and
src/lxml/_elementpath.py are derived from ElementTree and
cElementTree. See doc/licenses/elementtree.txt for the license text.

test.py, the test-runner script, is GPL and copyright Shuttleworth
Foundation. See doc/licenses/GPL.txt. It is believed the unchanged
inclusion of test.py to run the unit test suite falls under the
"aggregation" clause of the GPL and thus does not affect the license
of the rest of the package.

the doctest.py module is taken from the Python library and falls under
the PSF Python License.