/usr/include/gcr-3/ui/ is in libgcr-3-dev 3.20.0-5.1.
This file is owned by root:root, with mode 0o755.
..
/usr/include/gcr-3/ui/gcr-certificate-basics-widget.h
/usr/include/gcr-3/ui/gcr-certificate-details-widget.h
/usr/include/gcr-3/ui/gcr-certificate-renderer.h
/usr/include/gcr-3/ui/gcr-certificate-widget.h
/usr/include/gcr-3/ui/gcr-collection-model.h
/usr/include/gcr-3/ui/gcr-combo-selector.h
/usr/include/gcr-3/ui/gcr-deprecated.h
/usr/include/gcr-3/ui/gcr-enum-types.h
/usr/include/gcr-3/ui/gcr-failure-renderer.h
/usr/include/gcr-3/ui/gcr-import-button.h
/usr/include/gcr-3/ui/gcr-key-renderer.h
/usr/include/gcr-3/ui/gcr-key-widget.h
/usr/include/gcr-3/ui/gcr-list-selector.h
/usr/include/gcr-3/ui/gcr-prompt-dialog.h
/usr/include/gcr-3/ui/gcr-renderer.h
/usr/include/gcr-3/ui/gcr-secure-entry-buffer.h
/usr/include/gcr-3/ui/gcr-tree-selector.h
/usr/include/gcr-3/ui/gcr-ui.h
/usr/include/gcr-3/ui/gcr-unlock-options-widget.h
/usr/include/gcr-3/ui/gcr-viewer-widget.h
/usr/include/gcr-3/ui/gcr-viewer.h