Examine source code of Copy JIRA ticket key

{
  "browser_specific_settings": {
    "gecko": {
      "id": "@copy_jira_ticket_key"
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "page_action": {
    "browser_style": true,
    "default_icon": "button_icon.png",
    "default_title": "Copy ticket key"
  },
  "description": "A button to copy JIRA ticket key to clipboard.",
  "permissions": [
    "tabs",
    "clipboardWrite"
  ],
  "manifest_version": 2,
  "name": "Copy ticket number",
  "version": "0.1"
}