mongooseim: how to use backend action from documentation for mod privacy as an example?

Question

Is it possible to use backend actions from this documentation for rest api or from command line? https://esl.github.io/MongooseDocs/latest/modules/mod_privacy/

Also, I tried to use

[mod_privacy]
  default_list = "default_list"

[privacy_list.default_list]
  access = [{ allow = "roster" }]

in my configuration toml file but with no success..