Splitting the discussion from #10687 for adding the env() function together with the safe-area-inset-* keywords from CSS Environment Variables 1 to the Safe to Release pre-CR Exceptions section of the CSS Snapshot 2025.

Data to consider:

• Spec. status: ED (requires to publish a FPWD, see [css-env] Publish FPWD? #6729)
• implemented in all major browsers since 2020
• WPT: passing tests (experimental): Chrome: 42, Edge: 42, Firefox: 37, Safari: 37; interop: 37 / 42 (88.1%)
• Open issues: on GitHub: ~5, in spec.: 5

Summary: Very high interoperability, some open issues

Sebastian