includes - (available from IDE 1.6.10) (optional) a comma separated list of files to be added to the sketch as #include <...> lines. This property is used with the "Include library" command in the IDE. If the includes property is missing all the headers files (.h) on the root source folder are included.
original project was GPL3, so copying/license should be set to same one
from https://github.com/arduino/arduino/wiki/arduino-ide-1.5:-library-specification:
includes - (available from IDE 1.6.10) (optional) a comma separated list of files to be added to the sketch as #include <...> lines. This property is used with the "Include library" command in the IDE. If the includes property is missing all the headers files (.h) on the root source folder are included.
original project was GPL3, so copying/license should be set to same one
https://code.google.com/archive/p/clickbutton/