Comment by CharlesW

> How do small-scale embedded interpreters stack up?

Moddable's XS runtime is a wonder, with 99%+ ES2023 conformance even on devices running at 80 kHz with 45 KB of free memory. https://github.com/Moddable-OpenSource/moddable

QuickJS has somewhat higher requirements, but also a great candidate for embeddable mobile and desktop applications, and is well-regarded. https://bellard.org/quickjs/