[40four]

I already updated to v.72 so I don't know if they changed the default, never really noticed before. But now

  browser.tabs.insertRelatedAfterCurrent

defaults to 'true'. I agree this is expected behavior :)

[alimbada]

FF71 - default is also true.

Edit - default for this config variable could be platform specific; the above is based on Windows 10. I'll check on my MacBook tonight.

[40four]

True, I am on Windows 10 as well. If anyone needs to change it though, that is the related setting to check in about:config.

[megous]

That only applies when you open a tab by clicking on a link. If you do ctrl+t, you'll get new tab at the far right.

[the_duke]

That is toggled by "browser.tabs.insertAfterContent" ( vs insertRelatedAfterContent).

[lorenzhs]

You have a typo there, it's browser.tabs.insertAfterCurrent and browser.tabs.insertRelatedAfterCurrent (Current, not Content), just in case someone tries to copy and paste those into about:config

[nabergh]

This is correct and it also applies when middle clicking a link. That's where it really matters for me.

[jeltz]

Damn, another option I need to change when I upgrade Firefox. :( I liked the old default. I think I will have to start writing a user.js.