I'm afraid browsers stopped being "user agents" a long time ago. It's one of my pet peeves. They're agents of whichever company rolls them out. Basically Google

I'm afraid browsers stopped being "user agents" a long time ago. It's one of my pet peeves. They're agents of whichever company rolls them out. Basically Google or Mozilla. And they defer to the whims of whoever built the website you're visiting for a good chunk of their (insane) behaviour. If they were actual user agents, you would still have control over a lot of behaviour that's now been removed. Like actually remembering form fields you want to remember (instead, some websites tell the browser that it can't remember the user name, and the brower foolishly obeys). Or like copy/pasting text. Or like using the right mouse button (some websites disable it). Or like having control over keyboard shortcuts, which some websites override and which can't trivially be fixed. In my book, a user agent acts in my interests and on my behest. Sure, most of these behaviours can be corrected using browser extensions, but requiring a boatload of extensions to have an actual "user agent" doesn't make me happy.