/usr/include/opencv2/ximgproc/ is in libopencv-contrib-dev 3.2.0+dfsg-4build2.
This file is owned by root:root, with mode 0o755.
..
/usr/include/opencv2/ximgproc/deriche_filter.hpp
/usr/include/opencv2/ximgproc/disparity_filter.hpp
/usr/include/opencv2/ximgproc/edge_filter.hpp
/usr/include/opencv2/ximgproc/estimated_covariance.hpp
/usr/include/opencv2/ximgproc/fast_hough_transform.hpp
/usr/include/opencv2/ximgproc/fast_line_detector.hpp
/usr/include/opencv2/ximgproc/lsc.hpp
/usr/include/opencv2/ximgproc/paillou_filter.hpp
/usr/include/opencv2/ximgproc/seeds.hpp
/usr/include/opencv2/ximgproc/segmentation.hpp
/usr/include/opencv2/ximgproc/slic.hpp
/usr/include/opencv2/ximgproc/sparse_match_interpolator.hpp
/usr/include/opencv2/ximgproc/structured_edge_detection.hpp
/usr/include/opencv2/ximgproc/weighted_median_filter.hpp