Your New Tab webExtension has now been override by a better Extension:
The new better tab extension are now fully supporting Access to local files via local URL. The new working new tab extension you can find here:
https://addons.mozilla.org/en-US/firefox/addon/new-tab-homepage/ .
If have just found and testet it on Firefox 58.0.2 and it is perfectly working fine

Wirklich makellos und konfortabel, ich bin sehr zufrieden :)

totally hacked off that firefox do not allow local pages to be accessed as a home page
further this plugin then has probs with local pages

what on eart are firefox playing at??? haven't they heard of an INTRANET??? bizarre

thank you to the developer for your attempts to help us out on this

Great tab. Very helpful when using Gesturefy.

Works as advertised. Great plugin to deal with the annoying "feature" introduced in the new firefox version.

Thanks you /so/ much for producing this extension to unsuck another disgusting example of Mozilla's user-hating attitude.

A suggestion: There must be some bug report in Bugzilla to rectify this instance of user abuse by Mozilla. You could mention it on your extension page so that people who come there can follow the link to vote for that bug report.

Awesome !

Useful Add-on. Only sad that it is neccessary at all.

One of the best extensions for taking back control of your browser.

终于可以自定义 新标签页了

It's working perfectly, thank you.

Before installing this add-on I was a bit concerned by quite a few of the reviews saying it didn't work or was complicated to use.

Well, it worked perfectly for me, and was not in any way complicated. If you simply wish to set your newtab to open on a fixed webpage, go to the add-on options and type the desired URL into the text box. Done. It's that simple.

It's a bad reflection on Mozilla that this add-on is needed, but a huge thanks must go to the developer for creating it.

Mozilla really should have known better than to force a change so radical upon their userbase that it requires an add-on to return things to normality.

setzt dem Entwickler Wahnsinn der Firefox Guys -Giott sei Dank- den Riegel vor!!!

It works fine!

Danke dafür !!!