Access modifier issue on derived class

[DavideMininni-Fincons]

Checklist

• Did you run the analyzer with the --dev flag to get more information?
• Did you create a minimal reproduction in the playground?

Expected behavior
Hello guys :)
I was doing some refactoring on the Lit project I'm working on, and I found a little issue.

Let's say I have a base class B with an abstract public method open, and a derived class D that implement it.
Then I create a second derived class D2, and I want the method in D2 to not be public;
so I change the base method in B from public to protected.
This way, I would expect that D would expose a public open, while in D2 I would leave it as protected.

However, the public modifier from D is not taken into account when the manifest is created and the method is always marked as protected. I created a little demo here:
https://github.com/DavideMininni-Fincons/custom-element-manifest-demo/tree/main