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 
expect(data.url).toBeUndefined();
          expect(data.unsafeUrl).toEqual("../../0013/001346/134685E.pdf#4.3");
          expect(data.dest).toBeUndefined();
          expect(data.newWindow).toEqual(true);
          done();
        }, done.fail);
      }
    );
    it(
      "should correctly parse a GoToR action, containing a relative URL, " +
        'with the "docBaseUrl" parameter specified',
      function (done) {
        const actionDict = new Dict();
        actionDict.set("Type", Name.get("Action"));
        actionDict.set("S", Name.get("GoToR"));
        actionDict.set("F", "../../0013/001346/134685E.pdf");
        actionDict.set("D", "4.3");
        const annotationDict = new Dict();
        annotationDict.set("Type", Name.get("Annot"));
        annotationDict.set("Subtype", Name.get("Link"));
        annotationDict.set("A", actionDict);
        const annotationRef = Ref.get(489, 0);
        const xref = new XRefMock([
          { ref: annotationRef, data: annotationDict },
        ]);
        const pdfManager = new PDFManagerMock({
          docBaseUrl: "http://www.example.com/test/pdfs/qwerty.pdf",
        });
        AnnotationFactory.create(
          xref,