Examine source code of Combiner

{
  "manifest_version": 3,
  "default_locale": "en",
  "icons": {
    "16": "images/icons/16x16.png",
    "38": "images/icons/38x38.png",
    "48": "images/icons/48x48.png",
    "96": "images/icons/96x96.png",
    "128": "images/icons/128x128.png"
  },
  "commands": {
    "_execute_action": {
      "suggested_key": {
        "default": "Alt+Shift+E"
      }
    }
  },
  "content_scripts": [
    {
      "matches": [
        "https://www.pivotaltracker.com/*"
      ],
      "js": [
        "content/pivotal.js"
      ]
    },
    {
      "matches": [
        "https://basecamp.com/*"
      ],
      "js": [
        "content/basecamp.js"
      ],
      "all_frames": true,
      "run_at": "document_end"
    },
    {
      "matches": [
        "https://gitlab.digitalnz.org/*",
        "https://gitlab.com/*/*/merge_requests/new*",
        "https://github.com/*"
      ],
      "js": [
        "content/pull_request.js"
      ],
      "run_at": "document_end"
    }
  ],
  "action": {
    "default_title": "Boost",
    "default_popup": "popup/index.html?uilocation=popup",
    "default_icon": {
      "16": "images/icons/16x16.png",
      "38": "images/icons/38x38.png",
      "48": "images/icons/48x48.png",
      "96": "images/icons/96x96.png",
      "128": "images/icons/128x128.png"
    }
  },
  "permissions": [
    "activeTab",
    "clipboardWrite",
    "storage",
    "tabs",
    "contextMenus"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{23b14177-1ed1-4442-8d70-c085d0cc4bfe}"
    }
  },
  "name": "Combiner",
  "short_name": "Combiner",
  "version": "3.0.0"
}