Examine source code of Discord Inliner

{
  "manifest_version": 2,
  "name": "Discord Inliner",
  "version": "0.1.0",
  "description": "Displays videos and other content in the browser instead of showing a download prompt on Discord CDN servers by modifying the Content-Disposition header.",
  "permissions": [
    "webRequest",
    "webRequestBlocking",
    "*://cdn.discordapp.com/*",
    "*://media.discordapp.net/*"
  ],
  "icons": {
    "48": "icon.png"
  },
  "background": {
    "scripts": [
      "discord-inliner.js"
    ],
    "persistent": false
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{695da8bd-76c4-4273-9170-79b452eaf6a8}"
    }
  }
}