suggestion

Your extension is great and I have become proficient in Spanish in a short amount of time using it and plan on using it to learn French next. It is nearly perfect, I would just suggest adding a feature like the google translate extension where you can highlight anywhere on the browser and get the translation. I would add onto that by giving an option to have text to speech say the word and an option to add the word to a vocabulary list or even better the ability to add the word directly to anki. With this I would say your extension is complete and a masterpiece. I found an extension with these features, it’s called Yomitan.