Attach (recommended) or Link to PDF file here:
[docOficialPDF.php.pdf](https://github.com/mozilla/pdf.js/files/7159923/docOficialPDF.php.pdf)

Configuration:
- Web browser and its version: Firefox nightly
- Operating system and its version: linux debian
- PDF.js version: built-in viewer
- Is a browser extension: no

Steps to reproduce the problem:
1. Open the pdf page 2
2. Checkbox "Alta" in section 2 must be checked

It works fine with evince.
render() {
    
    if (this.data.alternativeText) {
      this.container.title = this.data.alternativeText;
    }
    return this.container;
  }
  _getKeyModifier(event) {
    const { isWin, isMac } = AnnotationElement.platform;
    return (isWin && event.ctrlKey) || (isMac && event.metaKey);
  }
  _setEventListener(element, baseName, eventName, valueGetter) {