The spec for this action:
https://www.adobe.com/content/dam/acom/en/devnet/pdf/pdfs/PDF32000_2008.pdf#G11.2111850
An example of a form using this action:
https://www2.illinois.gov/rev/forms/reg/Documents/reg-1-mr.pdf
constructor(data) {
    this.change = data.change || "";
    this.changeEx = data.changeEx || null;
    this.commitKey = data.commitKey || 0;
    this.fieldFull = data.fieldFull || false;
    this.keyDown = data.keyDown || false;
    this.modifier = data.modifier || false;
    this.name = data.name;
    this.rc = true;
    this.richChange = data.richChange || [];
    this.richChangeEx = data.richChangeEx || [];
    this.richValue = data.richValue || [];
    this.selEnd = data.selEnd || -1;
    this.selStart = data.selStart || -1;
    this.shift = data.shift || false;
    this.source = data.source || null;
    this.target = data.target || null;
    this.targetName = "";
    this.type = "Field";
    this.value = data.value || "";
    this.willCommit = data.willCommit || false;
  }
}
class EventDispatcher {