Examine source code of RunCode - OnlineCompiler

{
  "name": "RunCode - OnlineCompiler",
  "description": "Online compiler supporting 9 languages to run your basic code to learn or teach.",
  "version": "0.4",
  "manifest_version": 2,
  "browser_specific_settings": {
    "gecko": {
      "id": "02e709cbc2acca025a386670e678044fb15cdf27@onlinecompiler.io"
    }
  },
  "action": {
    "default_popup": "index.html",
    "default_icon": {
      "16": "code-16.png",
      "32": "code-32.png",
      "64": "code-64.png",
      "128": "code-128.png"
    }
  },
  "icons": {
    "16": "code-16.png",
    "32": "code-32.png",
    "64": "code-64.png",
    "128": "code-128.png"
  }
}