Item added, restocked, added to the shopping list, archived, or quick-added (ad-hoc); meals planned or drafted; tasks added or completed; records added; members joining or leaving. Task deletions, record deletions, and meal deletions are not logged (see the deleting/archiving FAQ above).
The top row of chips (All / Meals / Items / Tasks / Records) narrows the whole page to one category, and each of those reveals its own more specific sub-filters underneath - for example, Items breaks down further into Restocked, Added, Archived, Shopping list quick-add, and Added to shopping list.
Activity is grouped by date (Today, Yesterday, and so on), then by type within each day. Anything another household member did since you last opened the page is highlighted until you view it. Use Load more at the bottom to page through older history.
Free households see the last 14 days of activity; Premium sees full history.