Simple file parameter compatible with Pipeline. Transmits file contents as an environment variable in Base64 encoding, so it is best used with fairly small files. Example usage from Declarative Pipeline:

pipeline {
  agent any
  parameters {
    base64File 'FILE'
  }
  stages {
    stage('Example') {
      steps {
        sh 'echo $FILE | base64 -d > config.yaml'
      }
    }
  }
}