These settings are nothing to do with rooting your phone or flashing firmware etc. They are merely experimental and debugging features that you can toggle on and off. Although none of the features in the Developer options will break your phone or tablet, enabling some of them can cause unintended problems. Normally the menu is hidden, but this article explains how to unlock it with a few taps.
But why would you want to? Well, this article also gives a run-down of the current options available, with a short explanation for each. So, it is easy to scan this list and see if there is anything that may be of interest to you.
See https://www.xda-developers.com/android-developer-options/