Every supported data source has a data model that is used for the indexes and panels in GrimoireLab. The fields described in each data model are the fields that are expected from ElasticSearch after the enrichment process.
You can check out the data models of the supported data sources chaoss/grimoirelab-elk - schema. Each CSV file will have minimum two columns, name and type.
name refers to the actual field. Eg
type refers to the category of the field. Eg
Some CSV file might have four columns, name, type, aggregatable and description.
aggregatable refers to whether the field can be aggregated.
description gives a brief about the field.