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):

selEnd: event.target.selectionEnd,
            },
          });
        });
        const _blurListener = blurListener;
        blurListener = null;
        element.addEventListener("blur", event => {
          if (!elementData.focused || !event.relatedTarget) {
            return;
          }
          elementData.focused = false;
          const { value } = event.target;
          elementData.userValue = value;
          if (elementData.lastCommittedValue !== value) {
            this.linkService.eventBus?.dispatch("dispatcheventinsandbox", {
              source: this,
              detail: {
                id,
                name: "Keystroke",
                value,
                willCommit: true,
                commitKey: elementData.commitKey,
                selStart: event.target.selectionStart,
                selEnd: event.target.selectionEnd,
              },
            });
          }
          _blurListener(event);
        });
        if (this.data.actions?.Keystroke) {