I don't think Apple has specified the way they measure active users in their SEC filings, but if they followed the same methodology as the analytics in App Stor

I don't think Apple has specified the way they measure active users in their SEC filings, but if they followed the same methodology as the analytics in App Store Connect it would mean 125M people opened the News app for at least one session of at least 2 seconds. In Connect this doesn't map 1:1 to users (it shows active devices and is gated by the user's analytics privacy settings) but close enough.