The Bambu X1 and X1C printers purge filament from the nozzle when they start a print or change colors if you have an AMS (multi filament roll) unit. When purged this filament just drops out the back the the printer which for most people is inconvenient to clean up. Many different designs have been created to resolve this issue, some more elaborate than others. I went with this bucket like print that can be grabbed from the side to empty.
This has worked out really well and makes dealing with the waste filament so much easier.