/usr/include/evolution-3.10/libemail-engine/ is in evolution-dev 3.10.4-0ubuntu1.
This file is owned by root:root, with mode 0o755.
..
/usr/include/evolution-3.10/libemail-engine/camel-null-store.h
/usr/include/evolution-3.10/libemail-engine/camel-sasl-xoauth2.h
/usr/include/evolution-3.10/libemail-engine/e-mail-authenticator.h
/usr/include/evolution-3.10/libemail-engine/e-mail-enums.h
/usr/include/evolution-3.10/libemail-engine/e-mail-enumtypes.h
/usr/include/evolution-3.10/libemail-engine/e-mail-folder-utils.h
/usr/include/evolution-3.10/libemail-engine/e-mail-junk-filter.h
/usr/include/evolution-3.10/libemail-engine/e-mail-session-utils.h
/usr/include/evolution-3.10/libemail-engine/e-mail-session.h
/usr/include/evolution-3.10/libemail-engine/e-mail-store-utils.h
/usr/include/evolution-3.10/libemail-engine/e-mail-utils.h
/usr/include/evolution-3.10/libemail-engine/em-filter-folder-element.h
/usr/include/evolution-3.10/libemail-engine/em-vfolder-context.h
/usr/include/evolution-3.10/libemail-engine/em-vfolder-rule.h
/usr/include/evolution-3.10/libemail-engine/mail-config.h
/usr/include/evolution-3.10/libemail-engine/mail-folder-cache.h
/usr/include/evolution-3.10/libemail-engine/mail-mt.h
/usr/include/evolution-3.10/libemail-engine/mail-ops.h
/usr/include/evolution-3.10/libemail-engine/mail-tools.h
/usr/include/evolution-3.10/libemail-engine/mail-vfolder.h