Welcome to the forum 🙂
The frontend code (www directory) does not have a required build-step - its directly usable JavaScript. There are many ways to deploy vue.js - we´ve chosen a configuration where it can just be called without any build or package tools like webpack.
When we prepare a release, we run a minifier to reduce the code size and pack everything into a single file. We then add the current build number to this file in order to invalidate caches that worked with a previous version. This however is optional - as long as you clear your client cache after a change, it will work just fine.