Reproduction steps:
1. Open attached project "UIToolkit2.zip"
2. In Project window, right-click Packages/Local Package and select Create > UI Toolkit > UI Document
3. In Project window, observe Assets folder

Expected result: "Packages_NewUXMLTemplate" is created in the Packages folder
Actual result: "Packages_NewUXMLTemplate" is created in the Assets folder

Reproducible with: 1.0.0-preview.14 (2020.3.5f1, 2021.1.4f1)
Could not test with: 2018.4.34f1, 2019.4.24f1, 2021.2.0a14 (package errors break project)

Notes:
1. If instead of UI Document, you do Create > UI Toolkit > Panel Settings / Style Sheet / TSS Theme File, the asset is created in the Packages/Local Package folder.
2. It should be noted that "Packages_NewUXMLTemplate" is created in the Assets folder, but with a name that starts with "Packages_".