In the following spots a "MouseUp" eventName is being used, which does look inconsistent considering that the "Mouse Down"/"Mouse Enter"/"Mouse Exit" eventNames all have a space in them.
Is this inconsistency actually expected, or is it a simple typo? If the former, then a comment explaining *why* would be appropriate; otherwise we should just fix this :-)

 - https://github.com/mozilla/pdf.js/blob/25b84ce84c95ba06d1ee57e578672048269c39c1/src/display/annotation_layer.js#L806

 - https://github.com/mozilla/pdf.js/blob/25b84ce84c95ba06d1ee57e578672048269c39c1/src/display/annotation_layer.js#L945

 - https://github.com/mozilla/pdf.js/blob/25b84ce84c95ba06d1ee57e578672048269c39c1/src/display/annotation_layer.js#L1034

 - https://github.com/mozilla/pdf.js/blob/25b84ce84c95ba06d1ee57e578672048269c39c1/src/display/annotation_layer.js#L1168

/cc @calixteman 
result[2] = orderedX[2];
    } else {
      return null;
    }
    
    if (
      (orderedY[0] === rect1[1] && orderedY[1] === rect2[1]) ||
      (orderedY[0] === rect2[1] && orderedY[1] === rect1[1])
    ) {
      
      result[1] = orderedY[1];
      result[3] = orderedY[2];
    } else {
      return null;
    }
    return result;
  }
}
const PDFStringTranslateTable = [
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  0x2D8, 0x2C7, 0x2C6, 0x2D9, 0x2DD, 0x2DB, 0x2DA, 0x2DC, 0, 0, 0, 0, 0, 0, 0,
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  0x2013, 0x192, 0x2044, 0x2039, 0x203A, 0x2212, 0x2030, 0x201E, 0x201C,
  0x201D, 0x2018, 0x2019, 0x201A, 0x2122, 0xFB01, 0xFB02, 0x141, 0x152, 0x160,
  0x178, 0x17D, 0x131, 0x142, 0x153, 0x161, 0x17E, 0, 0x20AC
];
function stringToPDFString(str) {