is-leap-year.cul.js contains leap year code for calculang.
ESM output is-leap-year_esm/cul_scope_0.mjs, corresponding source/map and introspection info in is-leap-year.introspection.json was compiled by cul-js so that tests can readily be run using node. UMD bundle was excluded.
node ./test-is-leap-year.mjs
There is a UI on calculang.dev