Examine source code of Simple local 3D viewer

{
  "manifest_version": 2,
  "name": "k3d Viewer",
  "version": "1.0.0",
  "description": "Simple local 3D viewer for .obj and simple JSON meshes (no external GitHub references).",
  "permissions": [
    "activeTab",
    "storage"
  ],
  "browser_action": {
    "default_title": "k3d Viewer",
    "default_popup": "viewer.html"
  },
  "applications": {
    "gecko": {
      "id": "k3d-viewer@example.com"
    }
  }
}