Translations:FAQ/29/en

The : is used in an alias to send the following text simultaneusly from all connected profiles.

If you don't need such functionality, you could either disable or change the "send-text-to-all-games" alias, or altogether uninstall the package of the same name. To do that, go to the "Package Manager", select "send-text-to-all-games" and hit "uninstall".