/usr/include/gtksourceview-2.0/ is in libgtksourceview2.0-dev 2.10.5-3.
This file is owned by root:root, with mode 0o755.
..
/usr/include/gtksourceview-2.0/gtksourceview/
/usr/include/gtksourceview-2.0/gtksourceview/completion-providers/
/usr/include/gtksourceview-2.0/gtksourceview/completion-providers/words/
/usr/include/gtksourceview-2.0/gtksourceview/completion-providers/words/gtksourcecompletionwords.h
/usr/include/gtksourceview-2.0/gtksourceview/gtksourcebuffer.h
/usr/include/gtksourceview-2.0/gtksourceview/gtksourcecompletion.h
/usr/include/gtksourceview-2.0/gtksourceview/gtksourcecompletioncontext.h
/usr/include/gtksourceview-2.0/gtksourceview/gtksourcecompletioninfo.h
/usr/include/gtksourceview-2.0/gtksourceview/gtksourcecompletionitem.h
/usr/include/gtksourceview-2.0/gtksourceview/gtksourcecompletionproposal.h
/usr/include/gtksourceview-2.0/gtksourceview/gtksourcecompletionprovider.h
/usr/include/gtksourceview-2.0/gtksourceview/gtksourcegutter.h
/usr/include/gtksourceview-2.0/gtksourceview/gtksourceiter.h
/usr/include/gtksourceview-2.0/gtksourceview/gtksourcelanguage.h
/usr/include/gtksourceview-2.0/gtksourceview/gtksourcelanguagemanager.h
/usr/include/gtksourceview-2.0/gtksourceview/gtksourcemark.h
/usr/include/gtksourceview-2.0/gtksourceview/gtksourceprintcompositor.h
/usr/include/gtksourceview-2.0/gtksourceview/gtksourcestyle.h
/usr/include/gtksourceview-2.0/gtksourceview/gtksourcestylescheme.h
/usr/include/gtksourceview-2.0/gtksourceview/gtksourcestyleschememanager.h
/usr/include/gtksourceview-2.0/gtksourceview/gtksourceundomanager.h
/usr/include/gtksourceview-2.0/gtksourceview/gtksourceview-typebuiltins.h
/usr/include/gtksourceview-2.0/gtksourceview/gtksourceview.h