Steps to reproduce:

1. Browse Zabbix Templates
2. Zabbix Server Template
3. https://git.zabbix.com/projects/ZBX/repos/zabbix/browse/templates/app/zabbix_server
4. Notice that it heavily relies on a proxy master item called: zabbix[proxy,discovery]
5. Can't find it in the docs over at:
6. https://www.zabbix.com/documentation/current/en/manual/config/items/itemtypes/internal

Result:
https://www.zabbix.com/documentation/current/en/manual/config/items/itemtypes/internal

-> No Info about zabbix[proxy,discovery]
Expected:
Info about zabbix[proxy,discovery]