After the upgrade to webpack 4, we have a tiny extra music-metadata-browser bundle

[captbaritone]

Here's what it contains:

var map = {
	"./aiff/index": 246,
	"./apev2/index": 261,
	"./asf/index": 262,
	"./flac/index": 266,
	"./mp4/index": 268,
	"./mpeg/index": 271,
	"./ogg/index": 274,
	"./riff/index": 280,
	"./wavpack/index": 284
};


function webpackContext(req) {
	var id = webpackContextResolve(req);
	return __webpack_require__(id);
}
function webpackContextResolve(req) {
	var id = map[req];
	if(!(id + 1)) { // check for number or string
		var e = new Error("Cannot find module '" + req + "'");
		e.code = 'MODULE_NOT_FOUND';
		throw e;
	}
	return id;
}
webpackContext.keys = function webpackContextKeys() {
	return Object.keys(map);
};
webpackContext.resolve = webpackContextResolve;
module.exports = webpackContext;
webpackContext.id = 245;

Not sure how it got there, or what it does. My first thought was that Webpack was trying to automatically split out the individual parsers, but I don't see any bundles corresponding to those formats.

[captbaritone]

I wonder if @Borewit recognizes what this might be.

[captbaritone]

I tracked this down to what I think is a bug in Webpack: https://github.com/webpack/webpack/issues/9067