Examine source code of Container Color Toolbar

{
  "manifest_version": 2,
  "name": "Container Color Toolbar",
  "version": "0.2",
  "description": "Black theme toolbar following container color",
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "permissions": [
    "cookies",
    "theme",
    "contextualIdentities",
    "tabs"
  ],
  "applications": {
    "gecko": {
      "strict_min_version": "58.0"
    }
  },
  "icons": {
    "96": "img/containers.svg"
  }
}