Currently log[], logrt[], log.count[] and logrt.count[] items are documented in 2 places and both parts are essential for understanding. For example in 3.0 documentation:

1. https://www.zabbix.com/documentation/3.0/manual/config/items/itemtypes/zabbix_agent
2. https://www.zabbix.com/documentation/3.0/manual/config/items/itemtypes/log_items

Sometimes users search internet and find one of them and miss information from another one. Consider placing all information in one place.