Why does Snowpack complain a module not part of my project?

[turner]

I'm trying to move a project to Snowpack. The project has a number of npm packages, the dependency in package.json looks like this:

  "dependencies": {
    "data-modal": "github:igvteam/data-modal#544f5cf9",
    "igv-utils": "github:igvteam/igv-utils#v1.2.3",
    "igv-widgets": "github:igvteam/igv-widgets#c0041b1f",
    "kd3d": "github:turner/kd3d",
    "three": "^0.132.2"
  }

When I run snowpack dev I am seeing this error:
Package "color" not found. Have you installed it?

Huh? I don't use anything called "color". Can someone explain what is going on here?