Custom UserAgent String is a Firefox extension that lets you set a user-agent on a pe

[harlan4096]

So, Mozilla removed the site specific user-agent override setting from Firefox 71. There is a workaround for this, which as mentioned in the previous article is to use a global user-agent. The main issue with the workaround is that the set user-agent is then used on every site that you visit in the Firefox web browser.

And while I did warn you there maybe some side effects, initially I didn't notice many except for YouTube reverting to an older design. A few days later, when I visited a banking website, I found that it displayed a message which read something like "Upgrade your browser to access the website". Occasionally, one or two websites simply didn't load at all. I ignored those because I thought it was a server issue, but my friends told me they could access the sites from their browser (also Firefox).

That's when it hit me, of course the user-agent setting is what's messing with other websites. Sure enough, disabling the setting ensured that these websites worked as they normally do. Ironic, isn't it? You set the option to access some websites, but it ends up breaking others. I was looking for a fix and there is literally only one option, to use a user-agent switcher extension.

After some research and testing (and looking for alternatives to existing add-ons), I came across one which let me use user-agents on a per-site basis. The extension is called Custom UserAgent String. It is written by the author of the User-Agent Switcher revived add-on (not to be confused with the one made by Alexander Schlarb). It's amazing how many add-ons have the same name.

Functionally, both add-ons from Liner are quite similar, but the User-Agent Switcher extension only allows you to set a global user agent, which is what we wanted to fix here. Custom UserAgent String however lets you set a user-agent on a per-site basis. Perfect and it's quite simple to use too.

How to use Custom UserAgent String

Install the extension, click on its icon and then on the Options button. This should take you to a settings screen.

Ignore section I and skip to section II, which is captioned "Predefined UserAgent Strings". It has two drop-down menus, one for selecting the browser and Operating system, and the other for selecting the browser's user-agent.
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