Feature-Policy: publickey-credentials-get - HTTP
the http feature-policy header publickey-credentials-get directive controls whether the current document is allowed to access web authentcation api to create new public-key credentials, i.e, via navigator.credentials.get({publickey: ..., ...}).
... syntax feature-policy: publickey-credentials-get <allowlist>; <allowlist> an allowlist is a list of origins that takes one or more of the following values, separated by spaces: *: the feature will be allowed in this document, and all nested browsing contexts (iframes) regardless of their origin.
... definition of publickey-credentials-get directive, default allowlist.

Feature-Policy - HTTP
publickey-credentials-get controls whether the current document is allowed to use the web authentication api to retreive already stored public-key credentials, i.e.

HTTP Index - HTTP
142 feature-policy: publickey-credentials the http feature-policy header publickey-credentials directive controls whether the current document is allowed to access web authentcation api, i.e, via navigator.credentials.create({publickey: ...,...}) and navigator.credentials.get({publickey: ...,...}).