A person who can modify a Data Studio asset. (This usually refers to files created by other people)
Editors have Can Edit permission to the reports and data sources that have been shared with them. Editors can modify a report by adding or removing charts and controls, changing the dimensions and metrics, adding or removing data sources, altering the styling, or adding and removing pages. Editors can modify a data source by adding new calculated fields, changing field names, types, and aggregations, and adding descriptions.
By default, editors can share reports and data sources with either Can View or Can Edit permissions, but Owners can disable these options.