Description of the issue:
The SQRL protocol when used from the windows app when using Brave as the requesting browser, requires access from localhost to passive mixed-content image. Not when browsing the site, but when using the windows based login protocol, to login
This is true from any website using the protocol, but I will provide a specific example below. This is a very exciting 0 knowledge authentication protocol & I would love to be part of getting it working more smoothly w/ my favorite security focused browser. 
Exact URL of the website in question:
As mentioned this is an entire authentication protocol (early days, I hope). But a good example is the protocols forum site:
Did the issue present with default Shields settings? (yes/no)
Yes
As it’s requiring passive mixed-content image, A workaround may be in order (even if it requires a chrome webstore app, I think it is worth it. I may author said app, if it’s not biting off more than I can chew).
Does the site function as expected when Shields are turned off?
Yes perfectly
Is there a specific Shields configuration that causes the site to break? If so, tell us that configuration. (yes/no):
It’s related exactly to passive mixed-content image
Does the site work as expected when using Chrome?
Yes
Brave version (check About Brave):
Version 1.35.103 Chromium: 98.0.4758.102 (Official Build) (64-bit)
To further facilitate work-arounds or collaboration I’m included a link to my related post on the SQRL forums here. In the post on their forums I also linked to this Brave community post.