Back in the day I learned Javascript to create a Firefox extension called budaneki[1] that does basically that. It got quite popular but I abandoned it later since I no longer needed and didn’t have a business model.

Today I’m very happy with the Safari on MacOS as you’re can preview links. I like the Wikipedia implementation a lot, but as a Safari, I’m already used to have it everywhere.

[1] https://addons.mozilla.org/en-US/firefox/addon/budaneki/