https://www.zabbix.com/documentation/3.0/manual/config/visualisation/maps/links does not mention that it's possible to use {host:key.func(param)} macro for link labels.
Would be good too add this piece of info on the page.

Also, on page https://www.zabbix.com/documentation/3.0/manual/appendix/macros/supported_by_location a "Map labels" location mentioned for many macros, while it looks like they are supported only for icon labels, not link labels, except that one mentioned above.
Would be nice to separate these categories to be clear for zabbix users.

Tested using 3.0.5