as per https://www.zabbix.org/wiki/Docs/specs/ZBXNEXT-1575, displaying them during the initial development was "Discussed but will not be included"
as far as i recall, the rationale was that we could just show them, but to show them properly we would have to redesign that page quite a bit, so it was decided not to show them at all...

Thanks for the answer, but that was then, things maybe different now? I don't see why the Events tab would need to be changed that much to display internal events, but I'm more interested in being able to display all unsupported items, which from my point of view should probably be displayed in the Triggers tab. It is really great that we can get an email when an item becomes unsupported, but it would be even nice if we could view all unsupported items.

configuration -> hosts/templates, any item link, expand filter, set state to 'not supported' and clear host field

That view is awesome! The only thing it's missing is to be able to filter by maintenance status.

Zabbix could really use a web front-end overhaul. It has so many great features which are hard to find, or never even discovered.

I'd appreciate to optionally see internal events in a chronological order with proper filter functionality. This helps to see what recently happened without the need to create actions that fire lots of operations just to get this information.

Beside the fact that it sounds a little bit cumbersome to use e.g. MUA filter functions to query recent internal events, the alerter is due to lack of ZBXNEXT-2442 blocked quite quickly.

Inclusion in "Monitoring -> Events -> Source: Internal" would be awesome

This forum thread presents a good use case why it would be helpful to have this UI feature added.

Not having an easy way of viewing internal events means that problems with monitoring hosts and triggers on hosts themselves can't easily be identified and cleaned up, leading to other related issues.