This addresses ENG-3328. assets-webpack-plugin has this problem and webpack-manifest-plugin is officially recommended by Webpack.
Old JSON file looked like this:
{"browser":{"css":"prod.41af96d9c587.build.css","js":"prod.8860cda0687b.build.js"},"":{"wasm":"olm.983876380b11.wasm"}}
New JSON file looks like this:
{ "browser.css": "prod.41af96d9c587.build.css", "browser.js": "prod.3bf3c62a7a70.build.js", "olm.wasm": "olm.983876380b11.wasm" }