/usr/share/gtk-doc/html/ is in libgtksourceview2.0-doc 2.10.5-1ubuntu2.
This file is owned by root:root, with mode 0o755.
..
/usr/share/gtk-doc/html/gtksourceview-2.0/
/usr/share/gtk-doc/html/gtksourceview-2.0/GtkSourceBuffer.html
/usr/share/gtk-doc/html/gtksourceview-2.0/GtkSourceCompletion.html
/usr/share/gtk-doc/html/gtksourceview-2.0/GtkSourceCompletionInfo.html
/usr/share/gtk-doc/html/gtksourceview-2.0/GtkSourceCompletionItem.html
/usr/share/gtk-doc/html/gtksourceview-2.0/GtkSourceCompletionProposal.html
/usr/share/gtk-doc/html/gtksourceview-2.0/GtkSourceCompletionProvider.html
/usr/share/gtk-doc/html/gtksourceview-2.0/GtkSourceGutter.html
/usr/share/gtk-doc/html/gtksourceview-2.0/GtkSourceLanguage.html
/usr/share/gtk-doc/html/gtksourceview-2.0/GtkSourceLanguageManager.html
/usr/share/gtk-doc/html/gtksourceview-2.0/GtkSourceMark.html
/usr/share/gtk-doc/html/gtksourceview-2.0/GtkSourcePrintCompositor.html
/usr/share/gtk-doc/html/gtksourceview-2.0/GtkSourceStyle.html
/usr/share/gtk-doc/html/gtksourceview-2.0/GtkSourceStyleScheme.html
/usr/share/gtk-doc/html/gtksourceview-2.0/GtkSourceStyleSchemeManager.html
/usr/share/gtk-doc/html/gtksourceview-2.0/GtkSourceUndoManager.html
/usr/share/gtk-doc/html/gtksourceview-2.0/GtkSourceView.html
/usr/share/gtk-doc/html/gtksourceview-2.0/gtksourceview-2.0-Searching-in-a-GtkSourceBuffer.html
/usr/share/gtk-doc/html/gtksourceview-2.0/gtksourceview-2.0-completioncontext.html
/usr/share/gtk-doc/html/gtksourceview-2.0/gtksourceview-2.0.devhelp
/usr/share/gtk-doc/html/gtksourceview-2.0/gtksourceview-2.0.devhelp2
/usr/share/gtk-doc/html/gtksourceview-2.0/home.png
/usr/share/gtk-doc/html/gtksourceview-2.0/index.html
/usr/share/gtk-doc/html/gtksourceview-2.0/index.sgml
/usr/share/gtk-doc/html/gtksourceview-2.0/lang-reference.html
/usr/share/gtk-doc/html/gtksourceview-2.0/lang-tutorial.html
/usr/share/gtk-doc/html/gtksourceview-2.0/left.png
/usr/share/gtk-doc/html/gtksourceview-2.0/right.png
/usr/share/gtk-doc/html/gtksourceview-2.0/rn01.html
/usr/share/gtk-doc/html/gtksourceview-2.0/rn02.html
/usr/share/gtk-doc/html/gtksourceview-2.0/style-reference.html
/usr/share/gtk-doc/html/gtksourceview-2.0/style.css
/usr/share/gtk-doc/html/gtksourceview-2.0/up.png