Examine source code of Drag2Download

{
  "manifest_version": 2,
  "name": "Drag2Download",
  "version": "0.0.4",
  "description": "Effortlessly download images in Firefox by simply dragging them. This extension enhances productivity and convenience for users who frequently save images from the web.",
  "icons": {
    "64": "icons/icon.png"
  },
  "permissions": [
    "downloads",
    "activeTab"
  ],
  "background": {
    "scripts": [
      "background_script.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.mozilla.org/*",
        "<all_urls>"
      ],
      "js": [
        "content_script.js"
      ],
      "run_at": "document_end"
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "@drag2download"
    }
  }
}