Install this package to disable manylinux1 wheels when downloading from pip. The manylinux1 spec requires compliant packages to vendor binary dependencies inside the wheel that is distributed. Take for example a library which would (prior to manylinux1) dynamically link against libssl. As libssl received security patches, the system binaries would received updates from the OS's package manager. The python library which dynamically links would receive these updates for free without need to recompile, reinstall, etc. Under manylinux1, libssl is vendored inside the wheel. To receive security updates, you have to wait for the upstream to produce a new wheel and need to know to install a new version of that library. There's almost no visibility about these vendored wheels which makes managing them at scale impossible. As such, some may choose to ignore this standard.