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.#container.classList.remove("focused");
    if (this.#pinned || !this.isVisible) {
      return;
    }
    this.#container.hidden = true;
    this.#container.style.zIndex =
      parseInt(this.#container.style.zIndex) - 1000;
  }
  forceHide() {
    this.#wasVisible = this.isVisible;
    if (!this.#wasVisible) {
      return;
    }
    this.#container.hidden = true;
  }
  maybeShow() {
    if (!this.#wasVisible) {
      return;
    }
    this.#wasVisible = false;
    this.#container.hidden = false;
  }
  get isVisible() {
    return this.#container.hidden === false;
  }
}
class FreeTextAnnotationElement extends AnnotationElement {