JS files on NextCloud

Hi. In the source code on GitHub, GitHub - nextcloud/server: ☁️ Nextcloud server, a safe home for all your data, for apps/dashboard/src, I can see .vue and .js file. But when I build my own server on Docker, I couldn’t see the folder apps/dashboard/src. So, where are my .js and .vue files gone? I can see that the .vue file get compiled to plain .js during building, but I couldn’t see any .js files on apps/dashboard.

The dashboard was a separate app in the past but migrated to the core. Not sure if after the build, it shares compiles js-code with the main code parts as well… (I might be completely wrong).
So I’m not sure if you need to get the source code, build your own environment and then build the js-script stuff (with your modifications) from scratch: GitHub - nextcloud/server: ☁️ Nextcloud server, a safe home for all your data