Examine source code of Emoji

{
  "manifest_version": 2,
  "name": "Emoji",
  "version": "3.25",
  "author": "Saverio Morelli (Sav22999)",
  "description": "Insert emojis using a web browser, and customise the experience and the add-on in Settings.",
  "icons": {
    "16": "./img/icon-dark-16.png",
    "24": "./img/icon-dark-24.png",
    "48": "./img/icon-dark-48.png",
    "96": "./img/icon-dark-96.png"
  },
  "commands": {
    "_execute_browser_action": {
      "suggested_key": {
        "default": "Ctrl+Alt+A"
      }
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "emoji@saveriomorelli.com",
      "strict_min_version": "58.0"
    }
  },
  "browser_action": {
    "browser_style": true,
    "default_icon": {
      "16": "./img/icon-light-16.png",
      "24": "./img/icon-light-24.png",
      "48": "./img/icon-light-48.png",
      "96": "./img/icon-light-96.png"
    },
    "theme_icons": [
      {
        "dark": "./img/icon-dark-16.png",
        "light": "./img/icon-light-16.png",
        "size": 16
      },
      {
        "dark": "./img/icon-dark-24.png",
        "light": "./img/icon-light-24.png",
        "size": 24
      },
      {
        "dark": "./img/icon-dark-48.png",
        "light": "./img/icon-light-48.png",
        "size": 48
      },
      {
        "dark": "./img/icon-dark-96.png",
        "light": "./img/icon-light-96.png",
        "size": 96
      }
    ],
    "default_title": "Emoji",
    "default_popup": "./popup.html"
  },
  "permissions": [
    "storage"
  ],
  "optional_permissions": [
    "<all_urls>",
    "activeTab"
  ],
  "background": {
    "scripts": [
      "./js/background.js"
    ],
    "persistent": true
  }
}