Examine source code of ThumbnailCopy

{
  "manifest_version": 2,
  "name": "ThumbnailCopy",
  "version": "1.1.1resigned1",
  "homepage_url": "https://gregstoll.com/thumbnailcopy/",
  "description": "An easy way to copy the HTML for an image in a link (like a thumbnail image). Just use the \"Copy Image As Link\" context menu item. If you're often posting thumbnail images to blogs, etc. this could be very helpful!",
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content-script.js"
      ]
    }
  ],
  "permissions": [
    "activeTab",
    "contextMenus",
    "clipboardWrite"
  ],
  "applications": {
    "gecko": {
      "id": "thumbnailcopy@gregory.stoll"
    }
  }
}