To use these add-ons, you'll need to download Firefox.

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Tignit n uzegrir

Iceggiren i Vertical Tabs Reloaded

Vertical Tabs Reloaded sɣur Croydon

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Icegger-it Aseqdac Firefox 14190765
sɣur Aseqdac Firefox 14190765, 5 lat temu
I use macOS Catalina 10.15.4 and I can't hide horizontal tabs; without this feature the extension is much less useful.

Tiririt n ineflayen

yeffeɣ-d deg 5 lat temu
Please have a look in the add-on description, which second sentence is literally:

The default horizontal tab browser can't be hidden right now, that's a limitation in Firefox itself:
https://bugzilla.mozilla.org/show_bug.cgi?id=1332447

There is nothing that I can do about it.