How to reproduce:
1. Make sure to set the system region to one that uses ',' as a decimal point
2. Create a new project with any template
3. Create a new UI Document Asset (Asset > Create > UI Toolkit > UI Document)
4. Observe the Console

Another way to repro easily is to click on Assets > Update UXML Schema.

Expected result: No errors are thrown
Actual result: The “FormatException: The string '-3,402823E+38' is not a valid Single value.” error is thrown

Reproduced with: 2023.2.0b8, 2023.2.0f1, 2023.3.0a14
Not reproduced with: 2021.3.32f, 2022.3.13f, 2023.1.20f1, 2023.2.0b7

Reproduced on: Windows 10 (by reporter), Windows 11
Not reproducible on: No other environment tested

Notes:
1. Reproducible only in a new project
2. Reproduced with Region format set to “French (Canada)” or “German (Germany)”