Identify original/derived variable relationship in tidymodels recipe

In general you may not be able to figure this out. For example, if you create dummy variables, then PCA components, then other steps, you probably could not trace them.

For step_dummy(), you can though via the tidy() method:

library(tidymodels)
#> Registered S3 method overwritten by 'tune':
#>   method                   from   
#>   required_pkgs.model_spec parsnip
data(attrition)

rec <-
  recipe(Attrition ~ ., data = attrition) %>%
  step_normalize(all_numeric_predictors()) %>%
  step_dummy(all_nominal_predictors())

prepped <- prep(rec)
tidy(prepped, number = 2)
#> # A tibble: 43 × 3
#>    terms          columns              id         
#>    <chr>          <chr>                <chr>      
#>  1 BusinessTravel Travel_Frequently    dummy_4GB6U
#>  2 BusinessTravel Travel_Rarely        dummy_4GB6U
#>  3 Department     Research_Development dummy_4GB6U
#>  4 Department     Sales                dummy_4GB6U
#>  5 Education      College              dummy_4GB6U
#>  6 Education      Bachelor             dummy_4GB6U
#>  7 Education      Master               dummy_4GB6U
#>  8 Education      Doctor               dummy_4GB6U
#>  9 EducationField Life_Sciences        dummy_4GB6U
#> 10 EducationField Marketing            dummy_4GB6U
#> # … with 33 more rows

Created on 2021-11-08 by the reprex package (v2.0.0)