I don't know if this is a bug with npmjs.org or the repository structure. The package description shows the README-ipset file. I was a bit confused as I just read something about ipset.
Maybe it is better to just include the information in the main README file. I think "long" readme files are not a big problem.
Hi, thanks for spotting this :)
It seems to be some sort of "functionality" or bug with npm. I already reported it to npm guys (npm/npm#5583) but in the meantime, I solved it by moving the secondary README files to an inner folder /docs.
The README at https://www.npmjs.org/package/netfilter should be updated anytime soon to reflect the change.