Because the homepage is unavailable anymore.
Original author's note: (c) Lankier. Original license (the same GPLv3) is in COPYING file.
The code requires lxml.
Common python2 ./setup.py build && python2 ./setup.py install
will do the job.
But you have to install lxml -- read that page carefully!
If you use brew, then you may have to choose pip install
or you may have
to fix, say, fb2validator.py by inserting something like
import sys; sys.path.append('/where/your/lxml/module/was/installed/to')