The Gmail folder is one of the most well-known application logos of all time. This will change in a little while for a much different logo:
See:
It's just an M! from Mail, but it has more colors Google. It looks like an envelope, but it's a little more abstract. 
Η change comes as part of the redefinition of G Suite at Google workspace and will be released to users “τις επόμενες εβδομάδες”. Οι εφαρμογές Drive, Calendar, Meet, Docs, Sheets, και Slides will also get a new look:
