Examine source code of stay chill

{
  "name": "chill",
  "description": "Make websites less distracting. Focus on the content, not on notifications. ",
  "manifest_version": 2,
  "version": "1.0.3",
  "homepage_url": "https://github.com/levibostian/chill-web",
  "content_scripts": [
    {
      "matches": [
        "*://*.github.com/*"
      ],
      "js": [
        "scripts/github.js"
      ]
    },
    {
      "matches": [
        "*://*.slack.com/*"
      ],
      "js": [
        "scripts/slack.js"
      ],
      "css": [
        "styles/slack.css"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{0f4fdcc1-3d09-4701-850d-fe787602b32b}"
    }
  }
}