variableType options for variableAssignments of Endpoints

What kind of variableTypes can i assign to a variable in the variableAssignments option of an endpoint in Apps?


  "id": "app_eml_do_something",
  "type": "workflow",
  "async": true,
  "config": {
    "workflowId": "myID",
    "projectId": "myID",
    "variableAssignments": [
        "variableName": "example",
        "variableType": "STRING", 
        "$variableValue": {
          "type": "str",
          "value": "{{filters.someElement.something}}"
        "variableValue": "asdasd"

In my current case the variable is set through an filter. The filter has the multi select option. The variable is sent to a WF to implement some logic. I want to evaluate whether it makes sense to block the multi select in the WF. On the other hand, i possibly want to allow multiple values.
So far i know the following: When i take the variableType String i can either express that i want to have the first element of the filter values filters.someElement.something.values.0 or take all the values as a string formatted array filters.someElement.something.values.
However the WF VariableManager shows also the option DataTable. Can i make use of the DataTable option to retrieve the variables in a formatted representation? If so, what kind of variableType does allow this?