How to modify Umbraco v9 CMS generated files
I'm wondering if it is possible to make changes to the Umbraco CMS files. For example the "umbraco.controllers.min.js" file. These files get generated on build, so any changes I make get overwritten. I'm trying to make a small change to the backend UI, but I can't see where the files are even being generated from.
Short answer is: I wouldn't change anything in Umbraco files. It may be possible for you to create your own plugin (as part of your website, outside of the files Umbraco controls/generates) and override whatever it is you want changed (depends on what it is specifically), but Umbracos own files should be off limits. Otherwise you will run into problems when upgrading and such.
Edit: although... Those files shouldn't regenerate on build, I think, if you've installed Umbraco via Nuget and all that. Are you changing files directly in the Umbraco source repository?