The file headers contain
PCMLTOOLS is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
eg. https://github.com/fallingrock/pcmltools/blob/master/pcmltools/src/net/fallingrock/pcmltools/PcmlTools.java#L6
However, LICENSE has the GPLv2 license text not the GPLv3 license text.
You should also add info to the readme to clarify the "any later version" clause. The file headers include it, but it's good practice to give a statement for the project as a whole.
The file headers contain
eg. https://github.com/fallingrock/pcmltools/blob/master/pcmltools/src/net/fallingrock/pcmltools/PcmlTools.java#L6
However, LICENSE has the GPLv2 license text not the GPLv3 license text.
You should also add info to the readme to clarify the "any later version" clause. The file headers include it, but it's good practice to give a statement for the project as a whole.