Examine source code of RetroTxt

{
  "author": "Ben Garrett",
  "background": {
    "scripts": [
      "scripts/functions.js",
      "scripts/eventpage.js"
    ],
    "persistent": false
  },
  "browser_action": {
    "browser_style": true,
    "default_area": "navbar",
    "default_title": "RetroTxt",
    "theme_icons": [
      {
        "light": "assets/retrotxt_16-light.png",
        "dark": "assets/retrotxt_16.png",
        "size": 16
      },
      {
        "light": "assets/retrotxt_32-light.png",
        "dark": "assets/retrotxt_32.png",
        "size": 32
      }
    ]
  },
  "commands": {
    "_execute_browser_action": {
      "suggested_key": {
        "default": "Alt+R"
      },
      "description": "Switch the active tab between plain text and HTML displays"
    }
  },
  "default_locale": "en_US",
  "description": "Turn pieces of ANSI based text art and ASCII, NFO plain text into HTML.",
  "developer": {
    "name": "Ben Garrett"
  },
  "homepage_url": "https://retrotxt.com",
  "icons": {
    "16": "assets/retrotxt_128.svg",
    "32": "assets/retrotxt_128.svg",
    "64": "assets/retrotxt_128.svg"
  },
  "manifest_version": 2,
  "name": "RetroTxt",
  "omnibox": {
    "keyword": "rt"
  },
  "optional_permissions": [
    "tabs",
    "file:///*/",
    "*://*/*",
    "*://*.16colo.rs/*",
    "*://*.defacto2.net/*",
    "*://*.gutenberg.org/*",
    "*://*.scene.org/*",
    "*://*.textfiles.com/*",
    "*://*.uncreativelabs.net/*"
  ],
  "options_ui": {
    "browser_style": false,
    "open_in_tab": true,
    "page": "html/options.html"
  },
  "permissions": [
    "activeTab",
    "contextMenus",
    "storage",
    "tabs",
    "*://*.retrotxt.com/*"
  ],
  "short_name": "RetroTxt",
  "version": "4.2.1",
  "web_accessible_resources": [
    "css/*.css",
    "fonts/*.woff2",
    "html/options.html",
    "test/tests_browser.js"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "retrotxt@defacto2.net"
    }
  }
}