https://html.spec.whatwg.org/#hostensurecancompilestrings(callerrealm,-calleerealm)

8.1.3.13 HostEnsureCanCompileStrings(callerRealm, calleeRealm)
JavaScript contains an implementation-defined HostEnsureCanCompileStrings(callerRealm, calleeRealm) abstract operation. User agents must use the following implementation:​ [JAVASCRIPT]

Perform ? EnsureCSPDoesNotBlockStringCompilation(callerRealm, calleeRealm). [CSP]

affected by tc39/ecma262#1498 which adds parameters to HostEnsureCanCompileStrings to allow https://wicg.github.io/trusted-types/dist/spec/ to guard JavaScript source sinks.