What do group journal validation and substitution have in common?

According to the SAP S/4HANA Finance for Group Reporting Associates documents1, group journal validation and substitution have the following things in common:

Preconditions: Conditions that define when a validation or substitution rule is executed. Preconditions can be based on different dimensions or attributes of the data, such as company code, account type, etc.

Filtering logic: Logic that defines how data is filtered and selected for validation or substitution purposes. Filtering logic can be based on different operators or expressions, such as equal to, greater than, contains, etc.