The shaders exist in 2 locations, one is jpct_shaders.zip, the other is jPCT-AE.jar, I found some of them are not the same: defaultFragmentShaderTex1.src、defaultFragmentShader.src.
That might very well be. However, the actual result should be the same. The shaders in the zip are not used by default. They exist solely for project setups where the default shaders in the jar aren't exported in the final apk. This could happen on some strange setups but usually it's not a problem.