Plug-in in Duolingo

OK. Let's talk about Duolingo. As someone may know, I've started and am learning the Dutch language. And there's a website called Duolingo, which is fine.

And here I would like to note a reminder for myself in the future.

I introduced the following plug-ins.

https://github.com/arekolek/DuolingoCourseSwitcher
https://gist.github.com/halfdan/3a327abd242b3456d94a#file-goal-setter-user-js
https://monkeyguts.com/code.php?id=813

It's good to introduce. But you have to install a thing called Tampermonkey in order to allow your web browser (which is based on Google Chrome's system) to manage additional features.