Enables printing of background colors and images. Just uncheck "Enabled" whenever you want to revert to the default behavior.
Note: This extension is pretty useless now that Chrome's print dialog includes a "Background colors and images" checkbox, but I'll leave it published for a few months just in case someone needs it.
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This works by injecting :root{-webkit-print-color-adjust:exact} into every page's CSS. It takes effect immediately, and doesn't require reloading.
I imagine there's some reason why the Chrome devs haven't provided this as a default option yet. For instance, I've observed a few pages that look awful when printed with a background. So I suggest leaving this extension disabled until you come across a page that needs it.
I've published the (very short) source code under the Apache 2.0 license.