How to open incognito/private window with Selenium WD for different browser types?

Question

I want to test my test cases in private window or incognito window.

How to do the same in various browsers:

Answer 1

How to avoid Extensions in Private Mode prompt

For the actual geckodriver version I use:

    options.addArguments("-private");

It works fine but the annoying notification appears: Extensions in Private Mode.

I found the way to avoid it:

    options.addPreference("extensions.allowPrivateBrowsingByDefault",true);

As a result all extensions will run in private browsing mode without prompting at start