/usr/include/ is in libgspell-1-dev 1.2.2-1.
This file is owned by root:root, with mode 0o755.
..
/usr/include/gspell-1/
/usr/include/gspell-1/gspell/
/usr/include/gspell-1/gspell/gspell-checker-dialog.h
/usr/include/gspell-1/gspell/gspell-checker.h
/usr/include/gspell-1/gspell/gspell-enum-types.h
/usr/include/gspell-1/gspell/gspell-language-chooser-button.h
/usr/include/gspell-1/gspell/gspell-language-chooser-dialog.h
/usr/include/gspell-1/gspell/gspell-language-chooser.h
/usr/include/gspell-1/gspell/gspell-language.h
/usr/include/gspell-1/gspell/gspell-navigator-text-view.h
/usr/include/gspell-1/gspell/gspell-navigator.h
/usr/include/gspell-1/gspell/gspell-text-buffer.h
/usr/include/gspell-1/gspell/gspell-text-view.h
/usr/include/gspell-1/gspell/gspell.h