Error message in browser devtools console

[AKorezin]

Just noticed error message in browser devtools.
You are currently using minified code outside of NODE_ENV === "production". This means that you are running a slower development build of Redux. You can use loose-envify (https://github.com/zertosh/loose-envify) for browserify or setting mode to production in webpack (https://webpack.js.org/concepts/mode/) to ensure you have the correct code for your production build.
I've found out that this messages for the first time arrived in release 5.59.

I use self-built version. I wonder if it's just me or everyone?