config.yml

#! variables that need to be externally configurable
#! are specified in a data values schema file

#@ load("@ytt:data", "data")

list_with_a_map: #@ data.values.my_map

schema.yml

#@data/values-schema
---
my_map:
  key1: value1
  key2: value2

values.yml

#@data/values
---
my_map:
  key1: 3
  key2: value2