What is the problem this feature will solve?

The Temporal API is nearing completion in TC39 and is largely stable. It is not turned on by default in V8 just yet until it reaches stage 4 but platforms are starting to enable it by default. We ought to be able to go ahead and enable it by default in main

What is the feature you are proposing to solve the problem?

Enable Temporal by default but still marked as experimental

What alternatives have you considered?

No response