ljharbintl-fallback-symbol 
ECMA-402 Intl spec's internal FallbackSymbol.
This Symbol is well-known - shared across realms.
It is present in the following engines with the description "IntlLegacyConstructedSymbol" (spec):
- node >= 16
- Chrome >= 91
- Safari >= 14.1
- Firefox >= 54
It is present in the following engines with the description "IntlFallback": (The ES2017 Intl spec did not specify a description)
- node >=8 <16
- Chrome 57 - 90
When it is present, the package will export it; when not, it will export undefined.
Example
var IntlFallbackSymbol = require('intl-fallback-symbol');
var assert = require('assert');
assert(typeof IntlFallbackSymbol === 'symbol');
Tests
Simply clone the repo, npm install, and run npm test