The Label column allows you to specify a hierarchical location for the testplan. The label is a pipe ( | ) separated string that determines how a test is named in the test report and how it appears in the test selection user interface.
Because directories and files are created based on this label value, the label must not contain characters that create filenames that are considered illegal in your operating system. The following characters are considered legal in most cases:
Although testplans are grouped together and sorted alphabetically by label in the test-selection user interface, the order of execution is determined by its position in the testplan file. The Label column can be blank, but if no label is specified, the test is labeled as "Test n" where n is its numerical position in the testplan.