[Problem/Bug]: attachment:// scheme not working anymore

[Hyrius]

What happened?

I have links referencing attachment://file.ext that I handled programmatically, but it just stopped working and now I'm getting the Uri as about:blank#blocked in my events. Did anything change?

Importance

Blocking. My app's basic functions are not working due to this issue.

Runtime Channel

Prerelease (Edge Canary/Dev/Beta)

Runtime Version

133.0.3065.39

SDK Version

No response

Framework

Winforms

Operating System

Windows 11

OS Version

No response

Repro steps

It's a manually loaded HTML page containing links like <a href="attachment://file.jpg">attachment 1</a> and I used to be able to deal with them programmatically in the NavigationStarting event.
Now, e.Uri is about:blank#blocked.

Repros in Edge Browser

No response

Regression

Regression in newer Runtime

Last working version (if regression)

132.0.2957.140

[Hyrius]

I tried it in a new project and it worked as expected. I will keep trying to understand what's going on.

[Hyrius]

I did some more testing, and the issue didn’t occur because I was testing on another machine with Runtime 132.0.2957.140.
However, the exact same code doesn’t work (it navigates to about:blank#blocked) in Runtime 133.0.3065.39.
The SDK version appears to be irrelevant.
The issue is probably related to links added via JavaScript… I think?

WebView2CustomSchemeTest.zip