Examine source code of Firescroll

{
  "manifest_version": 2,
  "name": "Firescroll",
  "version": "1.9.12",
  "description": "Auto scroll for pages",
  "permissions": [
    "storage"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "vam80@mail.ru",
      "strict_min_version": "80.0"
    },
    "gecko_android": {
      "strict_min_version": "113.0"
    }
  },
  "icons": {
    "48": "icon.svg"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "lib/Constant.js",
        "lib/Container.js",
        "lib/ContainerPositionDto.js",
        "lib/ControlContainer.js",
        "lib/ControlPanel.js",
        "lib/ControlPanelState.js",
        "lib/ControlPanelStateActive.js",
        "lib/ControlPanelStateDisable.js",
        "lib/ControlPanelStateFast.js",
        "lib/ControlPanelStateNormal.js",
        "lib/DraggingState.js",
        "lib/Firescroll.js",
        "lib/HalfSkipButton.js",
        "lib/HalfSkipButtonArrowIcon.js",
        "lib/HalfSkipButtonSubArrowIcon.js",
        "lib/ScrollButton.js",
        "lib/ScrollButtonArrowIcon.js",
        "main.js"
      ]
    }
  ],
  "options_ui": {
    "page": "options.html",
    "browser_style": true
  }
}