Examine source code of RPC Selector

{
  "manifest_version": 2,
  "name": "RPC Selector",
  "description": "Changes all RPC calls to a custom URL",
  "version": "3.7.0",
  "icons": {
    "16": "images/icon-light-theme-16.png",
    "19": "images/icon-light-theme-19.png",
    "32": "images/icon-light-theme-32.png",
    "38": "images/icon-light-theme-38.png",
    "48": "images/icon-light-theme-48.png",
    "64": "images/icon-light-theme-64.png",
    "128": "images/icon-light-theme-128.png"
  },
  "permissions": [
    "webRequest",
    "webRequestBlocking",
    "webNavigation",
    "storage",
    "tabs",
    "http://*/*",
    "https://*/*"
  ],
  "applications": {
    "gecko": {
      "id": "4sliman4@gmail.com"
    }
  },
  "background": {
    "scripts": [
      "js/redirect.js",
      "js/background.js"
    ]
  },
  "options_ui": {
    "page": "popup.html",
    "chrome_style": true
  },
  "browser_action": {
    "default_icon": {
      "16": "images/icon-light-theme-16.png",
      "19": "images/icon-light-theme-19.png",
      "32": "images/icon-light-theme-32.png",
      "38": "images/icon-light-theme-38.png",
      "48": "images/icon-light-theme-48.png",
      "64": "images/icon-light-theme-64.png",
      "128": "images/icon-light-theme-128.png"
    },
    "default_title": "RPC Selector",
    "default_popup": "popup.html",
    "theme_icons": [
      {
        "dark": "images/icon-light-theme-16.png",
        "light": "images/icon-dark-theme-16.png",
        "size": 16
      },
      {
        "dark": "images/icon-light-theme-19.png",
        "light": "images/icon-dark-theme-19.png",
        "size": 19
      },
      {
        "dark": "images/icon-light-theme-32.png",
        "light": "images/icon-dark-theme-32.png",
        "size": 32
      },
      {
        "dark": "images/icon-light-theme-38.png",
        "light": "images/icon-dark-theme-38.png",
        "size": 38
      },
      {
        "dark": "images/icon-light-theme-48.png",
        "light": "images/icon-dark-theme-48.png",
        "size": 48
      },
      {
        "dark": "images/icon-light-theme-64.png",
        "light": "images/icon-dark-theme-64.png",
        "size": 64
      },
      {
        "dark": "images/icon-light-theme-128.png",
        "light": "images/icon-dark-theme-128.png",
        "size": 128
      }
    ]
  }
}