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):

this.#pinned = !this.#pinned;
    if (this.#pinned) {
      this.#show();
      this.#container.addEventListener("click", this.#boundToggle);
      this.#container.addEventListener("keydown", this.#boundKeyDown);
    } else {
      this.#hide();
      this.#container.removeEventListener("click", this.#boundToggle);
      this.#container.removeEventListener("keydown", this.#boundKeyDown);
    }
  }
  /**
   * Show the popup.
   */
  #show() {
    if (!this.#popup) {
      this.render();
    }
    if (!this.isVisible) {
      this.#container.hidden = false;
      this.#container.style.zIndex =
        parseInt(this.#container.style.zIndex) + 1000;
    } else if (this.#pinned) {
      this.#container.classList.add("focused");
    }
  }
  /**
   * Hide the popup.
   */
  #hide() {