Which statements are true regarding module and class names?

Module and class names in Puppet indeed must begin with a lowercase letter. This is a convention that helps distinguish module and class names from other elements within the Puppet codebase. Following this naming convention, starting with a lowercase letter ensures that the module or class is easily recognized by the Puppet parser and adheres to best practices regarding naming.

While it's true that module and class names can include numbers and underscores, they cannot start with either. This restriction is intended to maintain clarity and consistency in naming. Although a name like "main" is permitted, it is not an ideal practice to rely on it for clarity in larger environments, as well as to avoid potential conflicts or confusions that may arise in different contexts.

The conventions regarding naming help ensure that Puppet code is readable, maintainable, and adheres to community standards, which is particularly important when multiple users or teams may be interacting with the same codebase.