Specify a list of text labels associated with a source file.
This property has meaning only when the source file is listed in a target whose LABELS property is also set. No other semantics are currently specified.
© 2000–2016 Kitware, Inc.
© 2000–2011 Insight Software Consortium
Licensed under the BSD 3-clause License.
https://cmake.org/cmake/help/v3.7/prop_sf/LABELS.html