Examine source code of Time Blocker

{
  "manifest_version": 2,
  "name": "Time Blocker",
  "version": "0.9.0.2resigned1",
  "description": "A timer for working with the time blocking technique.",
  "icons": {
    "24": "icons/TimeBlocker24.png",
    "32": "icons/TimeBlocker32.png",
    "48": "icons/TimeBlocker48.png",
    "96": "icons/TimeBlocker96.png"
  },
  "permissions": [
    "storage",
    "activeTab",
    "<all_urls>"
  ],
  "background": {
    "scripts": [
      "background_scripts/timer_background.js"
    ]
  },
  "browser_action": {
    "default_icon": "icons/TimeBlocker32.png",
    "default_title": "Time Blocker",
    "default_popup": "popup/timer_control.html"
  },
  "commands": {
    "time_block": {
      "suggested_key": {
        "default": "Alt+Shift+W"
      },
      "description": "Starts a work session"
    },
    "small_break": {
      "suggested_key": {
        "default": "Alt+Shift+V"
      },
      "description": "Starts a small break session"
    },
    "big_break": {
      "suggested_key": {
        "default": "Alt+Shift+B"
      },
      "description": "Starts a big break session"
    },
    "stop": {
      "suggested_key": {
        "default": "Alt+Shift+S"
      },
      "description": "Stops the current session"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{20c71c6a-f5c3-4cdd-b926-81cf6afa2dec}"
    }
  }
}