What is the "Managed Challenge" Action in a Firewall Rule?

[jack_of_all_trades]

I’ve searched the community but could not find a proper answer.
This is not about the Firewall Log.

In the Firewall app when creating a Rule, a possible Action is Managed Challenge. Others are JS Challenge, Captcha, Block, Allow, …

What does Managed Challenge do?

p.s.: the help page does not mention this option: Firewall rules actions · Cloudflare Firewall Rules docs
p.p.s.: I’m using the free plan. Perhaps this option is only valid for paid plans? idk…

Edit: A few months later, the answer is mentioned in this blog post: The end of the road for Cloudflare CAPTCHAs

[thedaveCA]

Managed Challenge refers to a firewall rule that attempts to reduce the need to issue a CAPTCHA challenge to humans, it is briefly documented here.