The data list window has two tabs for displaying/editing current values:

Data Links tab

The data list's contents varies depending on the context of from where it was called.

When choices for a topic are available they can be chosen from a drop down menu. Otherwise changes can be made by typing in the the new values.

Mnemonic Constants tab

Mnemonic constants are human-readable symbols that represent numeric values.

Change the value of a mnemonic constant by typing in a new value.

The values are persistent (saved with the knowledge base).