Idea Summary
Let Items and Item Plugins be refreshable using (new) apex.item("XYZ").refresh or dynamic action refresh

(including “Page Items to Submit” in case of an item plugin)

Use Case
e.g: made up examples, maybe useless but i hope you get the idea

items: display only item displaying some data based on source type/language, like count(*) of something, date/time, etc.

item plugin: same as above but on the plugin level

Preferred Solution (Optional)
items: re-execute the query/plsql/etc in the source attribute

plugins: re-execute the render function