Get friendly text from Recurrence field on Schedules screen

It seems you'll have to generate this text yourself, based on the results from 

GET fmerest/v3/schedules/<category>/<name>

See https://docs.safe.com/fme/html/FME_REST/apidoc/v3/index.html#!/schedules/get_get_3

Sample result:

{
  "owner": "admin",
  "request": {
    "publishedParameters": [
      {
        "name": "SERVER_USERNAME",
        "value": "admin"
      },
      {
        "name": "BACKUP_DESTINATION",
        "value": "$(FME_SHAREDRESOURCE_BACKUP)ServerConfigPackage.fsconfig"
      },
      {
        "name": "BACKUP_APPEND_DATE",
        "value": "Yes"
      },
      {
        "name": "SERVER_PASSWORD",
        "value": "***"
      }
    ],
    "workspacePath": "Utilities/backupConfiguration/backupConfiguration.fmw",
    "TMDirectives": {},
    "NMDirectives": {
      "directives": [],
      "successTopics": [],
      "failureTopics": []
    }
  },
  "workspace": "backupConfiguration.fmw",
  "description": "Backup server configuration to an FME Server Configuration package. By default, the configuration file is saved to the Backup shared resources and the date and time of the backup are appended to the filename. The backup contains the repositories, services, security, notifications, schedules and data shared resources.",
  "sharable": true,
  "repository": "Utilities",
  "skipUntilJobComplete": false,
  "userName": "admin",
  "enabled": false,
  "recurrence": "interval",
  "taskType": "transformation",
  "unit": "DAY",
  "name": "Backup_Configuration",
  "interval": 1,
  "category": "Utilities",
  "begin": "2012-01-01T02:00:00+01:00"
}