Some App Icons have a lens symbol...

[ptkelly]

...or what looks like a lens symbol. Google Keep, Google Photos, Google Drive, and Google Docs do. There are also icons for those apps that don't have the "lens" symbol.

What is that?

 

[B. Diddy]

Can you show a screenshot? It probably differentiates between the Android app and the Chrome app/site.

 

[mustang7757]

Screen shot:

https://forums.androidcentral.com/showthread.php?t=413366