/usr/include/ImageMagick-6/ is in libmagickwand-6-headers 8:6.8.9.9-5+deb8u12.
This file is owned by root:root, with mode 0o755.
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/usr/include/ImageMagick-6/wand/
/usr/include/ImageMagick-6/wand/MagickWand.h
/usr/include/ImageMagick-6/wand/animate.h
/usr/include/ImageMagick-6/wand/compare.h
/usr/include/ImageMagick-6/wand/composite.h
/usr/include/ImageMagick-6/wand/conjure.h
/usr/include/ImageMagick-6/wand/convert.h
/usr/include/ImageMagick-6/wand/deprecate.h
/usr/include/ImageMagick-6/wand/display.h
/usr/include/ImageMagick-6/wand/drawing-wand.h
/usr/include/ImageMagick-6/wand/identify.h
/usr/include/ImageMagick-6/wand/import.h
/usr/include/ImageMagick-6/wand/magick-image.h
/usr/include/ImageMagick-6/wand/magick-property.h
/usr/include/ImageMagick-6/wand/magick-wand.h
/usr/include/ImageMagick-6/wand/magick_wand.h
/usr/include/ImageMagick-6/wand/method-attribute.h
/usr/include/ImageMagick-6/wand/mogrify.h
/usr/include/ImageMagick-6/wand/montage.h
/usr/include/ImageMagick-6/wand/pixel-iterator.h
/usr/include/ImageMagick-6/wand/pixel-wand.h
/usr/include/ImageMagick-6/wand/stream.h
/usr/include/ImageMagick-6/wand/wand-view.h