Over 300 warnings are generated on importing the "QuizU - UI Toolkit Sample

How to reproduce:
1. Import the "QuizU - UI Toolkit Sample" into the project
2. Observe the Console

Expected results: No warnings are generated on the import
Actual results: Over 300 warnings are generated on the import

Reproducible with: 2021.3.41f1, 2022.3.40f1, 6000.0.13f1

Reproducible on: macOS 14.5 Sonoma (M1)
Not reproducible on: No other environment tested

Notes:

• Unity 6 has slightly more warnings than older streams
• Some of the warnings are related to the Asset Import
• Most warnings are related to the UI Toolkit

A few warnings samples:
1. Assets/Unity Technologies/QuizU - A UI Toolkit demo/Demos/Templates/demo-template-container.uxml: Semantic - USS in 'style' attribute is invalid
2. Import of asset 'Assets/Unity Technologies/QuizU - A UI Toolkit demo/Quiz/UI/Uxml/VisualTreeAssets/portrait-warning.uxml' setup artifact dependency to 'Assets/Unity Technologies/QuizU - A UI Toolkit demo/_ThirdParty/Fonts/Roboto/Roboto-Black SDF.asset' but dependency isn't used and therefore not registered in the asset database.
3. Assets/Unity Technologies/QuizU - A UI Toolkit demo/Demos/7_EventsDemo/EventsDemo.uss (line 51): warning: Expected (<resource> | <url>) but found 'none'