Adding proxy config runs minified code on development server (ng serve)

Question

I am using proxy config setup in my angular 8 application.

I am using below command to start the server,

ng serve --port 4300 --proxy-config src/proxy.conf.json

After compiling successfully, i am getting below output

｢wdm｣: Compiled successfully.

[HPM] GET /styles.619f497b81ac514604bd.css -> https://<my-server-url>
[HPM] GET /runtime-es2015.cdfb0ddb511f65fdc0a0.js -> https://<my-server-url>
[HPM] GET /polyfills-es2015.7214e7f8190e9d99c095.js -> https://<my-server-url>
[HPM] GET /main-es2015.b11344c952cc03ebbfe1.js -> https://<my-server-url>
[HPM] GET /scripts.21a05e48cc6dd13c3d67.js -> https://<my-server-url>

I am not getting why it is bundling the files when using with proxy config.

Angular version: "@angular/cli": "~8.3.29"