Examine source code of Reading List Micro

{
  "manifest_version": 2,
  "name": "Reading List",
  "version": "0.6.0",
  "applications": {
    "gecko": {
      "id": "{7d1ebca6-ebf2-4bb5-bf10-b28a1892245e}",
      "strict_min_version": "73.0"
    }
  },
  "description": "Adds a reading list button",
  "homepage_url": "https://github.com/rewkha/firefox-reading-list",
  "icons": {
    "48": "icons/icon.svg"
  },
  "permissions": [
    "activeTab",
    "storage"
  ],
  "background": {
    "page": "background.html"
  },
  "sidebar_action": {
    "browser_style": true,
    "default_title": "Reading List",
    "default_panel": "sidebar/sidebar.html",
    "default_icon": "icons/icon-dark.svg"
  },
  "browser_action": {
    "default_icon": "icons/icon-dark.svg",
    "theme_icons": [
      {
        "light": "icons/icon-dark.svg",
        "dark": "icons/icon-light.svg",
        "size": 19
      }
    ],
    "default_title": "Open sidebar"
  },
  "options_ui": {
    "browser_style": true,
    "page": "options/options.html",
    "open_in_tab": false
  },
  "page_action": {
    "browser_style": true,
    "default_popup": "action/action.html",
    "default_icon": {
      "19": "icons/icon-dark-action.svg"
    },
    "default_title": "Add to reading list"
  }
}