Is it possible to customize the Chromium user agent string database?
 

We can enter a custom string, but I wish to choose from a list of several of them I make myself:

sample Developer Tools user agents

There are dozens of extensions https://chromewebstore.google.com/se...ypes=EXTENSION

Yes, but Chromium requires no extension to change our user agents. There's a file somewhere with a list of them, ideally not a ciphered binary.

Developer Tools uses system resources. I would use an extension if it used less or worked no less fluidly with the same level of privacy, e.g., you have to manually change your user agent with Developer Tools open for each tab & leave it open.