requestcontrol VS website-dark-mode-switcher

You can use Request Control with this rule. Import it from your settings.

You can use Request Control with a rule like the one in this example. To redirect all URLs, the path should be *.

For redirections you can also use the extensions Redirector and RequestControl. The first one is (IMHO) easier to configure, but the second one has more features.

If you're willing to create your own rules, you can replace all of these with Request Control.

You can redirect any URL pattern with extensions such as Request Control.

Install Request Control

You can use Request Control with this rule. Copy it to Notepad and save it on your computer, and then open the extension settings to import it.

Use an extension that lets you create custom redirects, like Request Control.

I use Request Control. See these example rules:

If the themes are in two separate files, for example, https://example.com/light.css and https://example.com/dark.css, it's possible to use Request Control to intercept requests to light.css and redirect them to dark.css instead. I do this with some sites that have separate themes but do not respect my prefers-color-scheme preference (dark).

To force dark/light mode (for websites that support it) while keeping my system/browser dark themes I use this addon https://github.com/rugk/website-dark-mode-switcher

That extension is listed as Dark Mode Website Switcher on AMO and doesn't have this feature: Darkening only specific domains.