What is a requirement for an expression to follow Appian's naming conventions?

An expression following Appian's naming conventions must be concise and directly descriptive. This requirement ensures that the names of expressions succinctly convey their purpose and functionality, making it easier for developers to understand and maintain the code. Clear and descriptive naming promotes readability and collaboration among team members, reducing the likelihood of confusion or misuse of expressions.

The other options do not align with Appian's naming conventions. Special characters are generally avoided, as they can complicate references and readability. Having an expression name end with numbers is not a standard requirement and may not add any meaningful clarity. While uniqueness is important, it refers to a broader context within applications rather than being a strict naming convention for expressions alone. Therefore, focusing on conciseness and descriptiveness is key to adhering to Appian's best practices.