Each linked file now has its own line on the dashboard card and on the Sheets and Excel pages: "Last write today 9:28 PM, 3 new rows". When a run also changed rows already in the file it says so, "3 new rows, 2 rows updated", and when a cleanup took rows out, "1 row removed". Times are shown in your own time zone.
When a sync runs and finds nothing to write, the line keeps the last write and adds "Checked today 9:40 PM, nothing new." Before a file's first write it reads "Waiting for its first transactions."
This line replaces "Last updated" on the Sheets and Excel pages, which moved on every check even when nothing was written. A file that has not been written to since this change keeps its "Last updated" date until its next write.
Nothing is added to your spreadsheet for this. The line lives in Sheetful.