ReTab for Safari to hop back to the last active /most recent tab

It's an essential feature when we were using Chrome, and since we switched to Safari haven't been able to find a usable extension - of the 2 we found, one doesn't work with the latest macOS, and the other crashes Safari several times a day. There are also a couple of questions posted here with many upvotes: How to cycle b/w my last used or most rec… - Apple Community, Last active tab safari - Apple Community

Thus we made ReTab for ourselves, where you can use Cmd+E or customized shortcut to go back to the last active tab, and it works on both macOS and iPad - hope you'd enjoy it too!