Chrome dev tools settings: where is the Experiments tab to Allow custom UI themes?

Question

I am using chrome version 36+

according to this page, I should be able to allow custom themes using the following instructions:

Installation Inst

Answer 1

1. Navigate to chrome://flags/

2. Find and enable Developer Tools experiments Mac, Windows, Linux, Chrome OS

3. Relaunch Chrome, open develop tool, setting, you will see experiments tab.

My Chrome version: Version 61.0.3163.100