I have couple open source NPM packages I develop together with other developers. In some of this packages I have less than 50% contributions in code. But I listed as contributor on NPM, just because I found this packages and did not update contributors list a long time.
So definitions does not matter when stats that author refers, does not include a developers who own over 50% code in repo, but includes me as contributor.
That's widely known problem of programmers to believe that world is perfect and all data are always actual. Actually it won't.
Maintainers are the ones responsible in the end for the state of the repo while contributors suggest changes.