Examine source code of Pinboard WebExtension

{
  "manifest_version": 2,
  "name": "Pinboard WebExtension",
  "short_name": "Pinboard",
  "version": "1.64",
  "description": "Easily add links to Pinboard. A remake of the official Pinboard extension.",
  "author": "George Pop",
  "homepage_url": "https://github.com/gapop/pinboard-webextension",
  "applications": {
    "gecko": {
      "id": "pinboard-webextension@helloworld.ro",
      "strict_min_version": "60.0"
    }
  },
  "icons": {
    "48": "icons/pinboard_icon_48.png",
    "96": "icons/pinboard_icon_96.png",
    "200": "icons/pinboard_icon.png"
  },
  "permissions": [
    "*://pinboard.in/*",
    "storage",
    "contextMenus",
    "activeTab",
    "notifications",
    "tabs"
  ],
  "browser_action": {
    "default_icon": {
      "16": "icons/toolbar_icon_16.png",
      "32": "icons/toolbar_icon_32.png",
      "48": "icons/toolbar_icon_48.png",
      "96": "icons/toolbar_icon_96.png"
    },
    "theme_icons": [
      {
        "dark": "icons/toolbar_icon_16.png",
        "light": "icons/toolbar_icon_16_light.png",
        "size": 16
      },
      {
        "dark": "icons/toolbar_icon_32.png",
        "light": "icons/toolbar_icon_32_light.png",
        "size": 32
      },
      {
        "dark": "icons/toolbar_icon_48.png",
        "light": "icons/toolbar_icon_48_light.png",
        "size": 48
      },
      {
        "dark": "icons/toolbar_icon_96.png",
        "light": "icons/toolbar_icon_96_light.png",
        "size": 96
      }
    ],
    "default_title": "Add to Pinboard",
    "default_popup": "popup_menu.html",
    "browser_style": true
  },
  "background": {
    "scripts": [
      "preferences.js",
      "main.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "https://pinboard.in/add",
        "https://pinboard.in/add*later=yes*"
      ],
      "js": [
        "link_saved.js"
      ]
    }
  ],
  "commands": {
    "save_dialog": {
      "description": "Save to Pinboard (opens dialog)"
    },
    "read_later": {
      "description": "Save to Read later"
    },
    "save_tab_set": {
      "description": "Save tab set"
    }
  },
  "options_ui": {
    "page": "preferences_page.html",
    "browser_style": true
  }
}