Good concept, have used in the past but removed for now. As others have noted, it opens the New Tab settings page rather than the selected New Tab. Also, removing the add-on didn't work.

Update to reply to developer response: "New Tabe Override still works." I'm giving you feedback that it doesn't, I could give you more information (Firefox on Dell laptop running Win 10 etc.) but a blanket response like that is odd. Why would I bother leaving this comment if I'd not had an issue?
To clarify "removing the add-on didn't work" in response to your answer - I just clicked on the remove button and the removal path (menus etc.) appeared but the add on was still present on Firefox. I did this a couple of times before it eventually went. Other add-ons have been successfully removed first time. I mentioned this because it seemed like useful feedback, I'm not smart enough to either develop apps or know whether it's possible for them to have an issue that can interfere with the removal process, although I have worked alongside software testers for enough years to believe that all kinds of unexpected behaviours can sometimes occur with software, so any feedback is usually useful in case the issue is a defect that impacts others, rather than just a temporary glitch or problem with the machine or browser.
It certainly could be something broken on my system, I'll be on the look out for any other apps not removing properly, thanks for the tip.

Does not load external css when used with local file due to firefox security limitations

Extension works perfectly except for keeping focus on the URL bar when the new tab is opened. I specifically wanted this addon for a website that would already have user input upon loading, and when it focuses on the URL bar I can't type in said user input.

I gave this 3 stars because it has one major failing. When atab is opened I want it to go to the newly opened tab. This addon does not do that.

Add menu item withouth checkbox to off this - is not good style. 3 now only. NN FF follower 4 add every day new interface items in the work process.

PS
Only ONE TIME configure this mod. WHY Menu Item show FOREWER? CRAP!!!!

There is an annoying white flicker when opening up a new tab if i use this :/.

When I open a new tab, it places the cursor before the test in the address bar instead of selecting the text in the adress bar. Typing in a search and pressing enter leads to a search containing my new tab url after my search terms

I tried it with a local file with a black background which turned white. It seems my dark theme is not handled well. The local page works well normally. I removed the addon for now.

I greatly appreciate the dedication and skill of the developer, yet this add-on grealty lacks in documentation.

Having disabled the chronicle in firefox there was no add-on icon and no error message whatsoever. I wasn't even aware there should be one and could not set up the new tab url.

I already quit on Firefox out of sheer frustration, but the next day I realized BY CHANCE that the error was in disabling the chronicle.

Sorry to be blunt, but software without documentation is a job half done. If you really want to help others, tell them how to use that nice add-on of yours.

Ein nützliches Feature, das eigentlich zur Grundausstattung gehören sollte. Es ist mir -bei allem respekt- unverständlich,dass Firefox solche Ad-Ons "ausgesourct" hat. Deshalb Dank an den Entwickler für seine Mühen. Gleiches gilt für die Palatzierung der Tabs (oben/unten), all das war zur Start-Zeit von firefox eleganter und vor allem intuitiv nachvollziehbarer gelöst. Warum -um alles in der Welt- verzichtet man auf Bewähres zu Gunsten neuer unpraktischerer Veränderungen?

Even with solid dark background color you still get white flashes. Clearly this needs to be solved at a deeper level than waiting for some HTML & CSS to load.

The extension used to work great!!! Loved it. But until I can resolve the following problem, I disabled it. Recently, when opening a new tab, there is a pop-up window in the upper right of the page that says something about New Tab Override changing a page, and there appears to be 2 buttons to push below the warning. Problem is, it pops up then disappears before I can read the whole thing, or have a change to push either of the buttons. VERY ANNOYING. Always happens with the first new tab, and occasionally happens when an additional tab is opened. Windows 10. Not sure if this is a New Tab Override problem, or a Firefox problem. Keep getting passed to someone else.