This was the Purebrowser upgrade:

@jonas.smedegaard did a

Which version of PureBrowser is this?

@jonas.smedegaard can i ask you to have a quick look in this issue description to see if this is worth investigating or if i am being silly

@Squid this issue is a clearly a duplicate of issue T814 were the cause of the problem with uBlock Origin has already been identified. And a temporary solution until the issue can be permanently resolved.

@jonas.smedegaard Ok, just repeated the steps above. The only difference was that i did not opened purebrowser before installing the 1.19.0 package from bullseye.

Here is a screenshot:

I just tested installing webext-ublock-origin_1.19.0+dfsg-2_all.deb from bullseye in a new image of PureOS Amber in a VM.

If it is the same issue then according to that issue tracker thread it should be fixed with ublock-origin/1.18.10+dfsg-1

Now that i am back online in front of a laptop, just to leave it registered here :)

It was my understanding that it was disabled by default.

Ok, testing from a VM image with purebrowser with no firefox compatibility mode, i was not able to reinstall uBlock Origin.

I am repeating the process in a VM with PureOS, with a version of purebrowser that does not have Firefox compatibility mode enabled

It is however *not* an acceptable solution to install addons from Mozilla

As an additional piece of information to this puzzle, a user has reported in the forums that uBlock Origin was also removed from his Firefox, but not blocked so the user could reinstall it as well:

thanks - what is probably more interesting is what you did in-between: Did you start PureBrowser while the addon was removed?

Don't know if it adds any new information to this issue. But i got uBlock Origin back by reinstalling it. Removed it and then install again

Upon rechecking, flathub is not offered as a default source.

@jonas.smedegaard i know you have been working on this issue of references of Mozilla and Firefox in purebrowser.

In the first case described here, updating grub (sudo update-grub) had no effect. Problem remains

This issue resurfaced. Noticed it by running an update at around 00h10 Central European Time