Actually, camelCase vs PascalCase
But I think they mean #PascalCase. At least, that's what their examples show.
For the differences between the two see, for example, here:
Camel Case vs. Snake Case vs. Pascal Case — Naming Conventions | Khalil Stemmler
Naming conventions bring consistency to your codebase which makes it easier to maintain. Camel case, pascal case, and snake case are the three most common naming conventions in modern programming languages.