I can only assume, but I'd think of cases where you write a workaround for a specific library or environment and then comment with something along the lines of

    // Have to do this because of other-project#122
    workaround();

Once that issue is resolved you'd see this as a warning/error notifying you that this workaround is no longer necessary. This would be helpful as often these workarounds just get forgotten over time and no-one really knows if they're still necessary or not.

Again, I'm assuming here, the npm page doesn't give much info.