Examine source code of PAW Invert

{
  "applications": {
    "gecko": {
      "id": "pawInvert@marion.dev"
    }
  },
  "permissions": [
    "tabs"
  ],
  "manifest_version": 2,
  "name": "PAW Invert",
  "version": "1.2resigned1",
  "description": "PAW will invert all images and videos in webpages so you can use your OS in negate mode and save your eyes.",
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "*://*/*"
      ],
      "exclude_matches": [
        "*://*.mozilla.org/*"
      ],
      "all_frames": true,
      "js": [
        "data/content_script/inject.js"
      ],
      "run_at": "document_start"
    }
  ],
  "browser_action": {
    "default_title": "pawInvert",
    "default_icon": {
      "16": "data/icons/dark/16.png",
      "32": "data/icons/dark/32.png"
    }
  },
  "icons": {
    "16": "data/icons/16.png",
    "32": "data/icons/32.png",
    "48": "data/icons/48.png",
    "64": "data/icons/64.png",
    "128": "data/icons/128.png"
  }
}