Identity: Names itself in its user agent only.
How to recognise it
- User agent contains
PhantomJS - Leaves automation traces in the page’s JavaScript globals
With Double Agent
Sessions from PhantomJS / Nightmare are labelled bot with agent_id: legacy.headless, and tagged in your analytics. Nothing is blocked unless you choose to. Install: https://doubleagent.so/install.md
Source: https://github.com/monperrus/crawler-user-agents