/etc/trafficserver/body_factory/ is in trafficserver 5.3.0-2ubuntu2.
This file is owned by root:root, with mode 0o775.
..
/etc/trafficserver/body_factory/default/
/etc/trafficserver/body_factory/default/.body_factory_info
/etc/trafficserver/body_factory/default/README
/etc/trafficserver/body_factory/default/access#denied
/etc/trafficserver/body_factory/default/access#proxy_auth_required
/etc/trafficserver/body_factory/default/access#redirect_url
/etc/trafficserver/body_factory/default/access#ssl_forbidden
/etc/trafficserver/body_factory/default/cache#not_in_cache
/etc/trafficserver/body_factory/default/cache#read_error
/etc/trafficserver/body_factory/default/congestion#retryAfter
/etc/trafficserver/body_factory/default/connect#dns_failed
/etc/trafficserver/body_factory/default/connect#failed_connect
/etc/trafficserver/body_factory/default/connect#hangup
/etc/trafficserver/body_factory/default/default
/etc/trafficserver/body_factory/default/interception#no_host
/etc/trafficserver/body_factory/default/redirect#moved_permanently
/etc/trafficserver/body_factory/default/redirect#moved_temporarily
/etc/trafficserver/body_factory/default/request#cycle_detected
/etc/trafficserver/body_factory/default/request#invalid_content_length
/etc/trafficserver/body_factory/default/request#no_content_length
/etc/trafficserver/body_factory/default/request#no_host
/etc/trafficserver/body_factory/default/request#scheme_unsupported
/etc/trafficserver/body_factory/default/request#syntax_error
/etc/trafficserver/body_factory/default/response#bad_response
/etc/trafficserver/body_factory/default/response#bad_version
/etc/trafficserver/body_factory/default/timeout#activity
/etc/trafficserver/body_factory/default/timeout#inactivity
/etc/trafficserver/body_factory/default/transcoding#unsupported
/etc/trafficserver/body_factory/default/urlrouting#no_mapping