Bus channel strip
You can only create bus channel strip objects in the Environment. In general, you will not need to do so, as all audio bussing (send/return routing via the Send slots of channel strips) is handled by aux channel strips.
Bus channel strips are primarily included for compatibility with earlier versions of Logic Pro, and for use with certain audio hardware devices.
Note: File > Project Settings > Audio > Automatic Management of Channel Strip Objects must be unselected if you want to create input channel strips. (It’s on by default.)