I'm concerned about an app on my child's phone. I saw an app icon in the notification area that looked strange (Andy Android head, slightly tilted as its icon).
How can I find out what app it is from just having seen that icon in the notification bar?
You need to investigate this on your own. There's a generic way to do this:
There are at least 4 possibilities:
If the phone has Android 4.1 or later you can long press the notification and see the App info:
Look that App icon up in the list of installed apps on the phone
Just click it and see what app starts
Go to the Play store and look through the installed apps on [phone] list
To access this you need to be logged in with your kid's Google account. On the phone itself this is automatically the case, on the PC you need to enter username/password.
If you drag down the notification bar you should be able to tell:
Before Android 7.1/API 25 (or maybe 7.0/24), if you long click it shows which app it's from. Also if you click the (i) button it takes you to the notifications settings for that app.
With Android 7.0/7.1, you should be able to see the app name as a header for the notification. Long clicking shows the notifications settings there in the notifications item directly.
With Android 8/API 26 you can also see the app name as a header. Long clicking shows which "notification channel" (new from API 26) the notification belongs to, and clicking "MORE SETTINGS" will allow you to see all channels and set the notifications settings for each channel specifically as well as for the app overall.