Vue Cli 3.0 where is the config file?

Where is the config files and why isn't it anywhere in the top level folders, etc?

The initial project doesn't require the file to exist because you just created a project with fresh "default" settings that don't require any config.

Just create it yourself. it's even mentioned in the README:

Many aspects of a Vue CLI project can be configured by placing a vue.config.js file at the root of your project. The file may already exist depending on the features you selected when creating the project.

(emphasis mine)

Edit: now to be found here: https://cli.vuejs.org/config/#global-cli-config

There is no need for "config" directory anymore. if you want to define "environment variables" you can do that in ".env" file

Just like:

VUE_APP_TITLE=Test

You can also create ".env" file for each environment

Like:

.env.development for development mode

.env.production for production mode.

For more information please read: https://cli.vuejs.org/guide/mode-and-env.html#example-staging-mode

The file by default does not exists as it was mentioned by Linus. You need to create manually vue.config.js file in a root location of your project, i.e. on the same level where is package.json.