Per Renato Rêgo on LRSUPPORT-31228:
The field Outputs > Path should be filled out with a specific data retrieved from the Data Provider and this information is displayed to the user. But, this field has a secret related to the character ";" that should be revealed to our customers. This character allows the Data Provider persist a value in the database different from the one displayed to the user. For instance, if the field Outputs > Path is filled out like:
Then, the value1 will be displayed to the user and the value2 will be persisted in the database.
IMHO, makes more sense add this information to the Official Docs instead of the KB: https://dev.liferay.com/discover/portal/-/knowledge_base/7-1/data-providers