Examine source code of Markdown Viewer Webext

{
  "manifest_version": 2,
  "name": "Markdown Viewer Webext",
  "version": "1.8.1",
  "author": "Keith L Robertson, Cimbali",
  "homepage_url": "https://github.com/KeithLRobertson/markdown-viewer",
  "description": "Displays Markdown documents beautified in your browser.",
  "applications": {
    "gecko": {
      "id": "{943b8007-a895-44af-a672-4f4ea548c95f}"
    }
  },
  "icons": {
    "48": "ext/markdown-mark.svg",
    "96": "ext/markdown-mark.svg"
  },
  "permissions": [
    "storage",
    "*://*/*.markdown",
    "*://*/*.md",
    "*://*/*.mdown",
    "*://*/*.mdwn",
    "*://*/*.mkd",
    "*://*/*.mkdn"
  ],
  "content_scripts": [
    {
      "matches": [
        "*://*/*.markdown",
        "*://*/*.MARKDOWN",
        "*://*/*.md",
        "*://*/*.MD",
        "*://*/*.mdown",
        "*://*/*.MDOWN",
        "*://*/*.mdwn",
        "*://*/*.MDWN",
        "*://*/*.mkd",
        "*://*/*.MKD",
        "*://*/*.mkdn",
        "*://*/*.MKDN",
        "file://*/*.markdown",
        "file://*/*.MARKDOWN",
        "file://*/*.md",
        "file://*/*.MD",
        "file://*/*.mdown",
        "file://*/*.MDOWN",
        "file://*/*.mdwn",
        "file://*/*.MDWN",
        "file://*/*.mkd",
        "file://*/*.MKD",
        "file://*/*.mkdn",
        "file://*/*.MKDN"
      ],
      "js": [
        "lib/markdown-it/dist/markdown-it.min.js",
        "lib/markdown-it-checkbox/dist/markdown-it-checkbox.min.js",
        "lib/markdown-it-emoji/dist/markdown-it-emoji.min.js",
        "lib/markdown-it-footnote/dist/markdown-it-footnote.min.js",
        "lib/markdown-it-fancy-lists/markdown-it-fancy-lists.js",
        "lib/highlightjs/build/highlight.min.js",
        "lib/katex/dist/katex.min.js",
        "lib/markdown-it-texmath/texmath.js",
        "ext/content.js"
      ]
    }
  ],
  "web_accessible_resources": [
    "lib/sss/*.css",
    "lib/highlightjs/build/styles/*.min.css",
    "lib/markdown-it-texmath/css/texmath.css",
    "lib/katex/dist/katex.min.css",
    "ext/menu.css"
  ],
  "options_ui": {
    "page": "ext/options.html",
    "browser_style": true
  }
}