dnscontrol/documentation/language-reference/domain-modifiers/FRAME.md

name	parameters	parameter_types
FRAME	name target modifiers...	name target modifiers... string string RecordModifier[]

{% hint style="info" %} This is provider specific type of record and not a DNS standard. It may behave differently for each provider that handles it. {% endhint %}

Namecheap

This is a URL Redirect record with a type of "Masked", it creates a framed HTML page to the target.

You can read more at the Namecheap documentation.