Examine source code of ENV Switcher

{
  "name": "ENV Switcher",
  "description": "Possible to swich between different environments",
  "version": "1.0",
  "manifest_version": 2,
  "permissions": [
    "storage",
    "tabs"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_popup": "popup.html"
  },
  "options_ui": {
    "page": "options.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "spamm@id-city.fr",
      "strict_min_version": "57.0"
    }
  },
  "content_scripts": [
    {
      "matches": [
        "*://*/*"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_end",
      "all_frames": true
    }
  ],
  "commands": {
    "open_env0": {
      "suggested_key": {
        "default": "Alt+Shift+J"
      },
      "description": "Open prod"
    },
    "open_env1": {
      "suggested_key": {
        "default": "Alt+Shift+K"
      },
      "description": "Open preprod"
    },
    "open_env2": {
      "suggested_key": {
        "default": "Alt+Shift+L"
      },
      "description": "Open dave (local)"
    },
    "refresh": {
      "suggested_key": {
        "default": "Alt+Shift+C"
      },
      "description": "Refresh URL"
    }
  }
}