bug#45179: qutebrowser stuck at Cloudflare 'browser checks'

[Ben Sturmfels]

On Sun, 24 Jan 2021, Mark H. Weaver wrote:

> ben--- via Bug reports for GNU Guix <bug-guix@gnu.org> writes:
>
>> I'm also having similar issues accessing gitlab.com with IceCat.
>> Installing the User Agent Switcher and setting to "Linux / Firefox 82"
>> fixed this for me.
>>
>> For context I also tried starting IceCat up in safe mode and switching
>> tracking protection back to "standard", but no good. The issue appears
>> to be that Cloudflare are essentially blocking niche user agents.
>
> The IceCat package in Guix sends the same user-agent string as the
> 'firefox-esr' package in Debian.

I've done a little more testing for interest sake - I still think
CloudFlare are at fault here.

If use a private tab and attempt to access a private GitLab repository I
get stuck at the CloudFlare "checking your browser message". Here's the
IceCat default user-agent string:

"Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Firefox/78.0"

If I install User Agent Switcher and do the same thing, it works. The
only difference in the user-agent string is the version number:

"Mozilla/5.0 (X11; Linux x86_64; rv:82.0) Gecko/20100101 Firefox/82.0"

If I try the same on Firefox ESR on Debian Buster, it works no problem,
but as Mark says, the Firefox user-agent string matches exactly to
IceCat:

"Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Firefox/78.0"

That suggests to me that there's more than the user-agent string at play
here.

Regards,
Ben