what is the monthly badge?

[Chess]

Duolingo notified me saying "Do a Greek lesson to get back on track for your monthly badge!" but what is a monthly badge and how to I get to them?

[Stasia]

Duolingo notified me saying "Do a Greek lesson to get back on track for your monthly badge!" but what is a monthly badge and how to I get to them?

It's a thing on the mobile version of Duolingo. I think it's supposed to motivate you to achieve 1000 XP each month, but there's no reward/no fireworks when you do, even if you achieve it early (like the first day of the month).

It's been a thing for a few months. If you click on the circle where it says whether you achieved your daily goal, it will show you how much XP you did per day in a month (click on "view challenge"). That's the only useful feature, it's like a mini-duome for the given month.