Identity: Names itself in its user agent only.
How to recognise it
- User agent contains
facebookexternalhit,meta-externalads
With Double Agent
Sessions from facebookexternalhit are labelled bot with agent_id: meta.facebookexternalhit, and tagged in your analytics. Nothing is blocked unless you choose to. Install: https://doubleagent.so/install.md
Source: https://developers.facebook.com/docs/sharing/webmasters/web-crawlers