Questions on GROUP BY I


So I was doing the Aggregate functions exercise “GROUP BY I” and had a question on why when I wrote

SELECT category, SUM(downloads)
FROM fake_apps;

Did it return with only the ‘News’ category and the total sum of downloads for the table.

I understand that by not adding in the GROUP BY line I didn’t specify the connection between category and SUM(downloads), but how did the system choose News as the category?

I believe my specific question is how exactly did the system respond to that line of code, because I don’t understand the logic it used to produce the result it did.