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):

link.href = this.linkService.getAnchorUrl("");
    link.onclick = () => {
      this.linkService.executeNamedAction(action);
      return false;
    };
    this.#setInternalLink();
  }
  /**
   * Bind attachments to the link element.
   * @param {Object} link
   * @param {Object} attachment
   */
  _bindAttachment(link, attachment) {
    link.href = this.linkService.getAnchorUrl("");
    link.onclick = () => {
      this.downloadManager?.openOrDownloadData(
        this.container,
        attachment.content,
        attachment.filename
      );
      return false;
    };
    this.#setInternalLink();
  }
  /**
   * Bind SetOCGState actions to the link element.
   * @param {Object} link
   * @param {Object} action
   */
  #bindSetOCGState(link, action) {