Is it possible to implement the subject macro?
(at least I didn't find it or similar in the list of supported currently - https://www.zabbix.com/documentation/3.4/manual/appendix/macros/supported_by_location).

A reason being is that there might be quite a few similar named items, e.g. "Page reads/sec", "Cache size", etc., that in fact belong to different "Applications" (i.e. different software).

Because of that sometimes it's hard to guess just based on a plain item name. And as the result of it, have to name some items like: "MS SQL Server, Cache Hit Ratio".

Had there been the subject macro, there wouldn't be any need in that.

Also, if that macro is used in the default action/trigger message, it'd be more informative.