Overview
Gets the branch id of a document.string myDocument.BranchId { get; }
Remarks
If used on a new document, that wasn't replicated/copied in some way (doesn't have branches), it will be null.
Example
var doc = $Documents.New('My Document');
doc.Publish(["myfolder", "otherfolder"]);
var id = doc.Id;
var existingDocument = $Documents.Get(id);
// Using Branch.Id after copying document:
var newVersion = $Documents.NewVersion(existingDocument.BranchId, 'My Document Version');
newVersion.Publish(["myfolder", "otherfolder"]);