Warning: at the moment this is an experimental template and it may be changed without warning or backwards compatibility. Please don't use it without a good reason to.
What this templates does: it appends the provided single item name to the contents of the non-locally scoped var page_exposed_items.
Why: This will make it possible to collect a list of every drop table item transcluded into a page, thus letting you later query sources of items.
{{Expose Item|<item name to expose>}}
Items are stored in following format separated by commas: ITEM_NAME+LEVEL_LOW+LEVEL_HIGH
The level low and high are read from vars page_expose_item_level_low and page_expose_item_level_high, defaulting to 1 and 12, respectively. Vars are set with Template:Expose Item/SetLevel, read with Template:Expose Item/ReadLevel, and reset with Template:Expose Item/ResetLevel. ResetLevel should be called by DropTableEnd, while SetLevel should be called by Template:DropTableLevel. Template:DropTableDivider will be the implementation details of DropTableLevel.