Examine source code of math-with-slackb

{
  "manifest_version": 2,
  "name": "math-with-slackb",
  "version": "0.1",
  "description": "Inject MathJax on Slack pages",
  "permissions": [
    "*://*.slack.com/*"
  ],
  "content_scripts": [
    {
      "matches": [
        "*://*.slack.com/*"
      ],
      "js": [
        "content.js"
      ],
      "all_frames": true
    }
  ]
}