Examine source code of Tiny calendar

{
  "icons": {
    "16": "icon16.plasmo.e7bcd3ac.png",
    "32": "icon32.plasmo.ce39377b.png",
    "48": "icon48.plasmo.3c17e113.png",
    "64": "icon64.plasmo.df317abe.png",
    "128": "icon128.plasmo.6a4310c5.png"
  },
  "manifest_version": 2,
  "browser_action": {
    "default_icon": {
      "16": "icon16.plasmo.e7bcd3ac.png",
      "32": "icon32.plasmo.ce39377b.png",
      "48": "icon48.plasmo.3c17e113.png",
      "64": "icon64.plasmo.df317abe.png",
      "128": "icon128.plasmo.6a4310c5.png"
    },
    "default_popup": "popup.html"
  },
  "version": "0.0.1",
  "author": "Paul Treanor",
  "name": "Tiny calendar",
  "description": "A minimal calendar popup that lets you open dates in Google Calendar easily",
  "browser_specific_settings": {
    "gecko": {
      "id": "{786c5a6a-6872-4268-b0ae-3788a3de076a}"
    }
  }
}