Open Existing per losnappas

** uhh, I updated it and.. it has a bug. I'll fix it tomorrow 3/26. Meanwhile you can always go backwards to v2, if you so choose. ** <- done. Reverted.
So I went back to the old version and put just 1 small fix in. THAT'S WHY IT'S NOW ASKING FOR THE PERMISSION.

Instead of opening duplicates of tabs, move the existing tab next to the current tab.

Does nothing if you open a link in the current tab instead of a New Tab. (This can be helpful and I personally prefer it this way.)

Explanation of required permissions:
"Access browser tabs": to close a duplicate tab that you're about to open, and to move the old tab.
"Access browser activity during navigation": temporarily logs the urls you have opened so it can know when a duplicate has been opened. The data is not sent anywhere or anything like that.
^^ that was dropped for v3. v3 wasn't good. Reverted and took it back in v4.