A row template is a predefined template for rows in a table. You can create your own line templates or edit the predefined line templates to adapt them to the specific arrangement of lines an organization wants in its tables.
Click on "Financials" > "Components" in the left menu. Under "Row templates", you will find all row templates.
When you have selected a row template, a purple information box may appear. It says which other tables are included and is affected if you change the row template.