It's a huge improvement to the dark theme on X (since X removed the dim-theme), but it does not work properly when creating images with Grok or adjusting images in your X-post. In both instances, the image doesn't show up until you disable this extension.
Also not everything gets colored in the blueish grey. For example: when replying to a post only the text field is dim, the original message in the background is black.
I've send the creator of this extension a message about this, but never got any reply.
So nice, but only does partially what it promises.