RUA had made me feel a tad safer for years. All these greedy bad guys (which is the new normal) made the internet , and the world a nightmare to live in. A few decent people try and resist. Giving away RUA is of one of the good guys.
Yet, some feel necessary to criticize and sleep. (and not rate 5*, mind you... . But we're never gonna survive, unless... Queue SEAL.

the best

this is exactly what I need, thank you!

Лучший на сегодня.
Best for today.

I really like Random User-Agent
I can not use the Random User-Agent on a site it is often detect and the site blocks me I would like to know the different settings to be more efficient with.

Thank you for your reply

在Android手机上（大约firefox 63开始）性能不良：我勾选safari on iphone，发现失灵后禁用再启用才会正常。

Works as well as any other User-Agent Swithcer, BUT...!
But the settings are super simple and straightforward to understand and to set up automated switching. That's why I chose this add-on before the other options!

Works great! I especially love the statistically inconspicuous pool of agents. It still provides a reasonable deal of slight even if you have to set it to a selection of a specific operating system and browser to prevent constant broken websites. For me this is an acceptable alternative to constantly curating a white-list.

The extension works great but broke too many sites so I uninstalled it. Be prepared for whitelisting several sites, otherwise you'll get broken functionality or infinite captchas because the site thinks you're a robot.