I wanted to add a reverse bowden to my bear so I modified the filament sensor cover to be able to receive a bowden tube without needing to add a coupler.
The reverse bowden mount that I prefer can be found here: https://github.com/VoronDesign/VoronUsers/blob/master/printer_mods/StvPtrsn/Parts_Jigs_and_Mods/Mods/Switchwire/PTFE_tube_side_mount.stl
The spool holder base can be found here: https://github.com/VoronDesign/VoronUsers/blob/master/printer_mods/StvPtrsn/Parts_Jigs_and_Mods/Mods/Switchwire/spool_holder_base_side.stl
The spool holder arm can be found here: https://github.com/VoronDesign/Voron-Switchwire/blob/master/STL/spool_holder.stl
The author remixed this model.