Examine source code of Spectrum Mute

{
  "manifest_version": 2,
  "name": "Spectrum Mute",
  "description": "Mute users in chat with right click. Works only on robertsspaceindustries.com/spectrum How to: https://youtu.be/UfkmjqG3czg",
  "version": "3.1resigned1",
  "applications": {
    "gecko": {
      "id": "SpectrumMute@dee690e60b047af7411ebc56c814511b"
    }
  },
  "browser_action": {
    "default_icon": "mute.png",
    "default_popup": "popup.htm"
  },
  "permissions": [
    "storage",
    "contextMenus",
    "tabs"
  ],
  "icons": {
    "16": "mute.png",
    "48": "mute.png",
    "128": "mute.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://robertsspaceindustries.com/spectrum/*"
      ],
      "js": [
        "content_script.js",
        "popup.js",
        "help.js"
      ]
    }
  ],
  "background": {
    "scripts": [
      "context.js",
      "background.js"
    ]
  }
}