Examine source code of Want My RSS

{
  "manifest_version": 2,
  "name": "Want My RSS",
  "version": "0.38",
  "description": "RSS features for Firefox",
  "author": "Mikhail Vyrtsev",
  "developer": {
    "name": "Mikhail Vyrtsev",
    "url": "https://github.com/Reeywhaar/want-my-rss"
  },
  "homepage_url": "https://github.com/Reeywhaar/want-my-rss",
  "icons": {
    "48": "icons/icon.svg",
    "96": "icons/icon.svg"
  },
  "background": {
    "page": "background.html"
  },
  "permissions": [
    "<all_urls>",
    "storage",
    "webRequest",
    "webRequestBlocking"
  ],
  "web_accessible_resources": [
    "show.html"
  ],
  "page_action": {
    "default_icon": "icons/bar-icon.svg",
    "default_title": "Subscribe to page",
    "browser_style": true,
    "pinned": true
  },
  "options_ui": {
    "page": "options.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{4d567245-e70d-466a-bb2f-390fc7fb25c2}",
      "strict_min_version": "64.0"
    }
  },
  "protocol_handlers": [
    {
      "protocol": "ext+rss",
      "name": "Want My RSS",
      "uriTemplate": "/show.html?url=%s"
    }
  ]
}