/etc/icinga2/features-available/ is in icinga2-common 2.8.1-0ubuntu2.
This file is owned by root:root, with mode 0o755.
..
/etc/icinga2/features-available/api.conf
/etc/icinga2/features-available/checker.conf
/etc/icinga2/features-available/command.conf
/etc/icinga2/features-available/compatlog.conf
/etc/icinga2/features-available/debuglog.conf
/etc/icinga2/features-available/elasticsearch.conf
/etc/icinga2/features-available/gelf.conf
/etc/icinga2/features-available/graphite.conf
/etc/icinga2/features-available/influxdb.conf
/etc/icinga2/features-available/livestatus.conf
/etc/icinga2/features-available/mainlog.conf
/etc/icinga2/features-available/notification.conf
/etc/icinga2/features-available/opentsdb.conf
/etc/icinga2/features-available/perfdata.conf
/etc/icinga2/features-available/statusdata.conf
/etc/icinga2/features-available/syslog.conf