Reading from the source code:

https://github.com/mozilla/pdf.js/blob/57d196e3497e77c81c19f852715ce79d9fb91492/src/display/annotation_layer.js#L2846

it appears to me it was not an intention to mark downloadManager as a required parameter in AnnotationLayerParameters:

https://github.com/mozilla/pdf.js/blob/57d196e3497e77c81c19f852715ce79d9fb91492/src/display/annotation_layer.js#L63

and AnnotationLayerBuilderOptions:

https://github.com/mozilla/pdf.js/blob/57d196e3497e77c81c19f852715ce79d9fb91492/web/annotation_layer_builder.js#L40

and it should be optional, similarly to accessibilityManager for example:

https://github.com/mozilla/pdf.js/blob/57d196e3497e77c81c19f852715ce79d9fb91492/web/text_layer_builder.js#L30

**Configuration:**
- PDF.js version: 2.11.174
- Is a browser extension: no

**What is the expected behavior? (add screenshot)**

`downloadManager` to be optional

**What went wrong? (add screenshot)**

`downloadManager` marked as required

Link to a viewer (if hosted on a site other than mozilla.github.io/pdf.js or as Firefox/Chrome extension):

for (const [baseName, eventName] of names) {
      if (eventName === "Action" || this.data.actions?.[eventName]) {
        if (eventName === "Focus" || eventName === "Blur") {
          elementData ||= { focused: false };
        }
        this._setEventListener(
          element,
          elementData,
          baseName,
          eventName,
          getter
        );
        if (eventName === "Focus" && !this.data.actions?.Blur) {
          
          this._setEventListener(element, elementData, "blur", "Blur", null);
        } else if (eventName === "Blur" && !this.data.actions?.Focus) {
          this._setEventListener(element, elementData, "focus", "Focus", null);
        }
      }
    }
  }
  _setBackgroundColor(element) {