You have been using JavaScript for 10 years. The test is simple: you have to open a package.json file and read it.
You wish you used a different name for your package, but some random internet person has squatted that name 7 years ago and never updated their package since.
Both main and browser fields are present, you sense traces of Isomorphic JavaScript.
The extensive pain you’ve experienced trying to importing ES5 modules from ESM modules and vice versa overwhelms you again.