Chronograf's Measurements & Tags interface

InfluxDB 1 Chronograf
1

I’m trying to understand what Chronograf is telling me;

image

I am generating this measurment from an injection via Node-RED InfuxDB out node

payload.measurment = OctopusPrice

Data is an array of an array of objects, e.g.;

[{"value_inc_vat":26.901,"time":1642977000000000000},{"source":"Agile"}]

source-1 seems to be auto generated. What is it and can I set that as part of the JSON payload?

[edit]
Yes so it is obvious suddenly - Source is the tag name, and Agile is the tag. The 1 simply says there is one tag. Doh! :man_facepalming: