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 
).then(({ data }) => {
        expect(data.annotationType).toEqual(AnnotationType.LINE);
        expect(data.lineCoordinates).toEqual([1, 2, 3, 4]);
        done();
      }, done.fail);
    });
  });
  describe("FileAttachmentAnnotation", function () {
    it("should correctly parse a file attachment", function (done) {
      const fileStream = new StringStream(
        "<<\n" +
          "/Type /EmbeddedFile\n" +
          "/Subtype /text#2Fplain\n" +
          ">>\n" +
          "stream\n" +
          "Test attachment" +
          "endstream\n"
      );
      const parser = new Parser({
        lexer: new Lexer(fileStream),
        xref: null,
        allowStreams: true,
      });
      const fileStreamRef = Ref.get(18, 0);
      const fileStreamDict = parser.getObj();
      const embeddedFileDict = new Dict();
      embeddedFileDict.set("F", fileStreamRef);
      const fileSpecRef = Ref.get(19, 0);
      const fileSpecDict = new Dict();
      fileSpecDict.set("Type", Name.get("Filespec"));