Examine source code of RepeatThat

{
  "manifest_version": 2,
  "name": "RepeatThat",
  "version": "1.0.2",
  "description": "Rewind/pause videos with any key combo or single F-key, media, numpad via RepeatThat app, no browser focus needed.",
  "permissions": [
    "activeTab",
    "tabs",
    "nativeMessaging",
    "storage",
    "scripting",
    "https://www.youtube.com/*",
    "https://www.youtube-nocookie.com/*"
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": true
  },
  "browser_action": {
    "default_icon": "icon-off.png"
  },
  "icons": {
    "48": "icon-activated.png",
    "128": "icon-activated.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*/*"
      ],
      "exclude_matches": [
        "*://*.edx.org/*",
        "*://*.khanacademy.org/*",
        "*://*.udemy.com/*",
        "*://*.coursera.org/*"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_idle",
      "all_frames": true
    },
    {
      "matches": [
        "*://*.coursera.org/*"
      ],
      "js": [
        "coursera-content.js"
      ],
      "run_at": "document_start"
    },
    {
      "matches": [
        "*://*.edx.org/*"
      ],
      "js": [
        "edx-content.js"
      ],
      "run_at": "document_start",
      "all_frames": true
    },
    {
      "matches": [
        "*://*.khanacademy.org/*"
      ],
      "js": [
        "khan-content.js"
      ],
      "run_at": "document_start",
      "all_frames": true
    },
    {
      "matches": [
        "*://*.udemy.com/*"
      ],
      "js": [
        "udemy-content.js"
      ],
      "run_at": "document_start",
      "all_frames": false
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "repeatthat@uncaria.io",
      "strict_min_version": "109.0"
    }
  }
}