I mean, depends on who puts it there? If the contributors list their emails knowingly for that purpose, that's one thing. If a tool leaks your NPM account email, which you have no control over, that's not exactly transparency.

You can see the Collaborator's NPM profile, where _they_ can set handles to contact them at. You can also get to their GitHub profile where they also can set handles to contact them at. If the tool made it easier to see those, then great.

These emails don't appear to be directly listed on NPM's website. Or correlated with Github/NPM profile. My guess is they're surfacing the email associated with that user's NPM account? Which is not otherwise obviously listed. And the only way you could control it is by also affecting who is an owner of the NPM project itself.

If that is the case, then contributor's emails are being 'leaked' without their say-so or probably knowledge, and without any particular way of managing it. Meanwhile they've already listed perfectly good ways of being 'reachable'.