/usr/include/ImageMagick/ is in libmagickwand-dev 8:6.6.9.7-5ubuntu3.9.
This file is owned by root:root, with mode 0o755.
..
/usr/include/ImageMagick/wand/
/usr/include/ImageMagick/wand/MagickWand.h
/usr/include/ImageMagick/wand/animate.h
/usr/include/ImageMagick/wand/compare.h
/usr/include/ImageMagick/wand/composite.h
/usr/include/ImageMagick/wand/conjure.h
/usr/include/ImageMagick/wand/convert.h
/usr/include/ImageMagick/wand/deprecate.h
/usr/include/ImageMagick/wand/display.h
/usr/include/ImageMagick/wand/drawing-wand.h
/usr/include/ImageMagick/wand/identify.h
/usr/include/ImageMagick/wand/import.h
/usr/include/ImageMagick/wand/magick-image.h
/usr/include/ImageMagick/wand/magick-property.h
/usr/include/ImageMagick/wand/magick-wand.h
/usr/include/ImageMagick/wand/magick_wand.h
/usr/include/ImageMagick/wand/mogrify.h
/usr/include/ImageMagick/wand/montage.h
/usr/include/ImageMagick/wand/pixel-iterator.h
/usr/include/ImageMagick/wand/pixel-wand.h
/usr/include/ImageMagick/wand/stream.h
/usr/include/ImageMagick/wand/wand-view.h