Examine source code of DevTools Media Panel

{
  "name": "Media Panel",
  "short_name": "Media",
  "version": "2.6",
  "author": "Karolien Koorts, Gerald Squelart, Michael Froman",
  "applications": {
    "gecko": {
      "strict_min_version": "54.0a1"
    }
  },
  "devtools_page": "devtools.html",
  "description": "Devtools panel that displays information about media and webrtc",
  "icons": {
    "48": "images/icon-48.png",
    "96": "images/icon-96.png"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "js": [
        "inject.js"
      ],
      "matches": [
        "https://*/*"
      ],
      "all_frames": true,
      "match_about_blank": true,
      "run_at": "document_start"
    }
  ],
  "permissions": [
    "tabs",
    "<all_urls>",
    "activeTab",
    "downloads"
  ],
  "manifest_version": 2
}