The extension adds a button to toggle on/off problem tags on codeforces
The rating tag (difficulty tag) is considered separate and is marked as a spoiler (see the image below) and can be toggled on/off independently of problem(topic) tags
You will need a userscript manager like Tamper Monkey to use the script
For the script to work properly, please note that "show tags for unsolved problems" should be OFF in your general setting on codeforces