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):

event.target.disabled = !event.detail.editable;
          },
        };
        this._dispatchEventFromSandbox(actions, jsEvent);
      });
      selectElement.addEventListener("input", event => {
        const exportValue = getValue( true);
        storage.setValue(id, { value: exportValue });
        event.preventDefault();
        this.linkService.eventBus?.dispatch("dispatcheventinsandbox", {
          source: this,
          detail: {
            id,
            name: "Keystroke",
            value: selectedValues,
            changeEx: exportValue,
            willCommit: false,
            commitKey: 1,
            keyDown: false,
          },
        });
      });
      this._setEventListeners(
        selectElement,
        null,