/usr/include/cegui-0.8.7/CEGUI/RendererModules/OpenGL/ is in libcegui-mk2-dev 0.8.7-2.
This file is owned by root:root, with mode 0o755.
..
/usr/include/cegui-0.8.7/CEGUI/RendererModules/OpenGL/ApplePBTextureTarget.h
/usr/include/cegui-0.8.7/CEGUI/RendererModules/OpenGL/GL.h
/usr/include/cegui-0.8.7/CEGUI/RendererModules/OpenGL/GL3FBOTextureTarget.h
/usr/include/cegui-0.8.7/CEGUI/RendererModules/OpenGL/GL3GeometryBuffer.h
/usr/include/cegui-0.8.7/CEGUI/RendererModules/OpenGL/GL3Renderer.h
/usr/include/cegui-0.8.7/CEGUI/RendererModules/OpenGL/GLFBOTextureTarget.h
/usr/include/cegui-0.8.7/CEGUI/RendererModules/OpenGL/GLGeometryBuffer.h
/usr/include/cegui-0.8.7/CEGUI/RendererModules/OpenGL/GLRenderer.h
/usr/include/cegui-0.8.7/CEGUI/RendererModules/OpenGL/GLXPBTextureTarget.h
/usr/include/cegui-0.8.7/CEGUI/RendererModules/OpenGL/GeometryBufferBase.h
/usr/include/cegui-0.8.7/CEGUI/RendererModules/OpenGL/GlmPimpl.h
/usr/include/cegui-0.8.7/CEGUI/RendererModules/OpenGL/RenderTarget.h
/usr/include/cegui-0.8.7/CEGUI/RendererModules/OpenGL/RenderTarget.inl
/usr/include/cegui-0.8.7/CEGUI/RendererModules/OpenGL/RendererBase.h
/usr/include/cegui-0.8.7/CEGUI/RendererModules/OpenGL/Shader.h
/usr/include/cegui-0.8.7/CEGUI/RendererModules/OpenGL/ShaderManager.h
/usr/include/cegui-0.8.7/CEGUI/RendererModules/OpenGL/StandardShaderFrag.h
/usr/include/cegui-0.8.7/CEGUI/RendererModules/OpenGL/StandardShaderVert.h
/usr/include/cegui-0.8.7/CEGUI/RendererModules/OpenGL/StateChangeWrapper.h
/usr/include/cegui-0.8.7/CEGUI/RendererModules/OpenGL/Texture.h
/usr/include/cegui-0.8.7/CEGUI/RendererModules/OpenGL/TextureTarget.h
/usr/include/cegui-0.8.7/CEGUI/RendererModules/OpenGL/ViewportTarget.h
/usr/include/cegui-0.8.7/CEGUI/RendererModules/OpenGL/WGLPBTextureTarget.h