In a game on messenger what is the hallow arrow in the top right corner for?

To use secret messages, 1.open up the Facebook messenger app and tap the compose message icon in the top right of screen.2.You should see a list of your contacts and, again in the top right of the screen, the word "Secret" - tap it and select the friend you want to talk to. (Quick note - if you're using an Android phone you'll see a small switch with a padlock instead)3.The app will ask you to set the phone you're using as your default device - meaning the conversation won't show up on any other phones or tablets you've got linked to your Facebook account. Hit the "Make Default" option to continue.4.You'll now be able to have a conversation that is encrypted end-to-end. You'll know it's secret because Facebook has given the chat window a natty black makeover.5.If you want to set your messages to self-destruct, click the Set Timer (clock face on Android) and select how long you want the message to remain after it's been read.