docs: protected final Set<String> getAcceptedMimeTypes() {
          if (acceptedMimeTypesSet == null) {
              // No defaults are registered, so use those non-defaults ...
              acceptedMimeTypesSet = new HashSet<String>();
              for (String mimeType : acceptedMimeTypes) {
                  if (mimeType == null) continue;
                  mimeType = mimeType.trim();
                  if (mimeType.length() == 0) continue;
                  acceptedMimeTypesSet.add(mimeType);
              }
          }
          return acceptedMimeTypesSet;
      }