Examine source code of Snap.as

{
  "manifest_version": 2,
  "name": "Snap.as",
  "short_name": "Snap.as",
  "description": "Quickly upload your photos.",
  "version": "1.0.1",
  "icons": {
    "16": "icon16.png",
    "48": "icon48.png",
    "128": "icon128.png"
  },
  "browser_action": {
    "default_icon": {
      "38": "icon76.png"
    },
    "default_title": "Upload to Snap.as"
  },
  "background": {
    "scripts": [
      "popup.js"
    ]
  },
  "permissions": [
    "webRequest",
    "notifications",
    "clipboardWrite",
    "https://*.snap.as/"
  ],
  "web_accessible_resources": [
    "uploader.html"
  ],
  "externally_connectable": {
    "matches": [
      "*://*.snap.as/*"
    ]
  }
}