Thanks for making this!

Didn't realize, how much I needed this, das exactly what it's supposed to

Inside tab groups, the new tab doesn't open right next to the current tab but two tabs to the right.

Works as intended with some problems, especially in newer versions. Be careful since it can crash Firefox if you're using Wayland in Linux.

It works, except for the fact that it jumps you to the end all the same. Fixing that would make this perfect. Much better than the default, though.

browser.tabs.insertAfterCurrent didn't work for me, but this works perfectly

Wonderful. This addon is still needed If you want to open your tabs in recent-to-last order if opening many of them at once ()