  - Open https://mozilla.github.io/pdf.js/web/viewer.html
  - Open a pdf with some XFA (for example the on in https://github.com/mozilla/pdf.js/issues/13679#issue-937616350)

The pdf is not correctly displayed because `enableXfa` is false.

@Snuffleupagus, the pref is set to true in Firefox nightly, is there anything blocking setting it to true in the web viewer ?  
this.renderingDone = true;
    if (!this.enhanceTextSelection) {
      const endOfContent = document.createElement("div");
      endOfContent.className = "endOfContent";
      this.textLayerDiv.appendChild(endOfContent);
    }
    this.eventBus.dispatch("textlayerrendered", {
      source: this,
      pageNumber: this.pageNumber,
      numTextDivs: this.textDivs.length,
    });
  }
  /**
   * Renders the text layer.
   *
   * @param {number} [timeout] - Wait for a specified amount of milliseconds
   *                             before rendering.
   */
  render(timeout = 0) {
    if (!(this.textContent || this.textContentStream) || this.renderingDone) {
      return;