Comment 3 for bug 1748019

The PyPI wheels are manylinux1 builds (PEP 513) but statically link the latest libxml2 and libxslt versions (at the time of their creation). That's probably why they do not conflict with the external libraries.

Fedora (and most Linux distros) most likely build their lxml package against the system provided libraries, which totally makes sense for them. But it also means that multiple users of libxml2 will use the same library, and their configuration might conflict. Specifically, if both try to use different URL/file resolvers and configure them globally in libxml2, then their will definitely be a conflict between the two.