/usr/include/libecap/ is in libecap3-dev 1.0.1-3ubuntu3.
This file is owned by root:root, with mode 0o755.
..
/usr/include/libecap/adapter/
/usr/include/libecap/adapter/service.h
/usr/include/libecap/adapter/xaction.h
/usr/include/libecap/common/
/usr/include/libecap/common/area.h
/usr/include/libecap/common/autoconf.h
/usr/include/libecap/common/body.h
/usr/include/libecap/common/body_size.h
/usr/include/libecap/common/delay.h
/usr/include/libecap/common/errors.h
/usr/include/libecap/common/forward.h
/usr/include/libecap/common/header.h
/usr/include/libecap/common/libecap.h
/usr/include/libecap/common/log.h
/usr/include/libecap/common/memory.h
/usr/include/libecap/common/message.h
/usr/include/libecap/common/name.h
/usr/include/libecap/common/named_values.h
/usr/include/libecap/common/names.h
/usr/include/libecap/common/options.h
/usr/include/libecap/common/registry.h
/usr/include/libecap/common/version.h
/usr/include/libecap/host/
/usr/include/libecap/host/host.h
/usr/include/libecap/host/xaction.h