Examine source code of FB2 Reader

{
  "description": "Read FB2 e-Books with Firefox",
  "manifest_version": 2,
  "name": "FB2 Reader",
  "version": "1.0.1",
  "homepage_url": "https://github.com/tymofij/fb2reader",
  "icons": {
    "16": "icons/icon-16.png",
    "24": "icons/icon-24.png",
    "32": "icons/icon-32.png",
    "48": "icons/icon-48.png",
    "64": "icons/icon-64.png",
    "96": "icons/icon-96.png",
    "128": "icons/icon-128.png"
  },
  "permissions": [
    "webRequest",
    "webRequestBlocking",
    "*://*/*.fb2*",
    "*://*/*.FB2*",
    "*://*/*.Fb2*",
    "*://*/*.fB2*"
  ],
  "background": {
    "scripts": [
      "jszip.js",
      "streamfilter.js"
    ]
  },
  "applications": {
    "gecko": {
      "id": "fb2reader@clear.com.ua",
      "strict_min_version": "58.0"
    }
  },
  "content_scripts": [
    {
      "matches": [
        "file:///*.fb2",
        "file:///*.FB2",
        "file:///*.Fb2",
        "file:///*.fB2"
      ],
      "js": [
        "tools.js",
        "local.js"
      ]
    }
  ],
  "web_accessible_resources": [
    "icons/icon-16.png",
    "icons/icon-16-2x.png",
    "css/fb2.css",
    "css/html.css",
    "css/print.css",
    "tools.js"
  ]
}