Wow, that's an amazingly polished extension! I couldn't help but sniff out the [1] github link, and noticed you were using vue.js, I used vue too with my extension [2] Newsit, check it out to see how you can deploy to both Chrome and Firefox (as the extension APIs are almost standardised).
The only issue I found, was that the popup switcher doesn't show up on the new tab page, which makes it a little confusing.
The only issue I found, was that the popup switcher doesn't show up on the new tab page, which makes it a little confusing.
[1] https://github.com/dvdvdmt/popup-tab-switcher
[2] https://github.com/benwinding/newsit/