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 
];
      for (const nonStandardOrder of nonStandardOrders) {
        dict.set("QuadPoints", nonStandardOrder);
        expect(getQuadPoints(dict, rect)).toEqual([
          [
            { x: 10, y: 20 },
            { x: 20, y: 20 },
            { x: 10, y: 10 },
            { x: 20, y: 10 },
          ],
        ]);
      }
    });
  });
  describe("Annotation", function () {
    let dict, ref;
    beforeAll(function (done) {
      dict = new Dict();
      ref = Ref.get(1, 0);
      done();
    });
    afterAll(function () {
      dict = ref = null;
    });
    it("should set and get valid contents", function () {
      const annotation = new Annotation({ dict, ref });
      annotation.setContents("Foo bar baz");
      expect(annotation.contents).toEqual("Foo bar baz");
    });
    it("should not set and get invalid contents", function () {