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):

const p = document.createElement("p");
    p.classList.add("popupContent");
    p.dir = dir;
    const lines = str.split(/(?:\r\n?|\n)/);
    for (let i = 0, ii = lines.length; i < ii; ++i) {
      const line = lines[i];
      p.append(document.createTextNode(line));
      if (i < ii - 1) {
        p.append(document.createElement("br"));
      }
    }
    return p;
  }
  #keyDown(event) {
    if (event.altKey || event.shiftKey || event.ctrlKey || event.metaKey) {
      return;
    }
    if (event.key === "Enter" || (event.key === "Escape" && this.#pinned)) {
      this.#toggle();
    }
  }
  /**
   * Toggle the visibility of the popup.
   */
  #toggle() {