Permissions-Policy: execution-while-not-rendered

The HTTP Permissions-Policy header execution-while-not-rendered directive controls whether tasks should execute in frames while they're not being rendered (e.g. if an iframe is hidden or has display: none set).

Specifically, where a defined policy blocks execution of task rendering while content is not being rendered, while that condition is true, that content will be put in the frozen state as defined in the Page Lifecycle API. This stops execution of freezable tasks such as JavaScript timers (e.g. setTimeout()) and fetch() callbacks.

Permissions-Policy: execution-while-not-rendered=<allowlist>;