Found in

• 106.0b5 (2022-09-28)

Affected versions

• Firefox Nightly 107.0a1
• Beta 106.0b5

Affected platforms

• all

Steps to reproduce

1. Set any other color from the Change Colorway menu.
2. Reach about:firefoxview in a new tab.
3. Reach about:FirefoxView in a second tab.

Expected result

• The about:firefoxview url should not be case sensitive and it should redirect to the same page.
• The about:FirefoxView url should be replaced with the default "Search with google" text and the page background color should be the one set in the Colorway menu.

Actual result

• The about:firefoxview url text is replaced with Search with google and the Background color remains the one set in the Colorway menu.
• The about:FirefoxView url text remains inside the urlbar and the page background color is white as if the user was redirected to a different page.

I don't think we care enough to fix that - URLs are case sensitive, and you can see this if you open e.g. about:Neterror? or about:Newtab (which respectively don't work at all and don't get the background colour either), without using the autocomplete (which auto-lowercases it for you). We don't support users inputting mis-cased about: URLs.