This is an optical endstop mount used with stock 100mm extrusion spacing while using warham's Upgraded XY Carriage. It is made to pass the wire through and have it exit on the side in the rear and run down the extrusion. I used 2 m3x10 screws and m3 square nuts to hold the sensor in, and 1 m5x8 and t nut to hold housing to upper Y extrusion (mount is slotted to adjust height). You have to ever so slightly sand the end of the optical endstop where it will touch the extrusion.
I have also added a remixed xy carriage for the side with the Y end stop, I have opened up the gap between the 2 upper rod clamps 3mm to allow you more side to side adjustment of the Y endstop flag to work with my Y endstop mount.
I have also remixed the end cap to eliminate the holes for the x-rods since my Zyltech kit rods didn't go past the xy carriage.
I have attached the XY carriage I used (10mm Y rods, 8mm X rods) with nut inserts no brass inserts needed. as well as the extended X flag.
warham has many other versions for different rod configurations here - https://www.thingiverse.com/thing:2469902
NanoTech Carbon Fiber
Y flag holder in Carbon Fiber PETG, xy carriage in MakerGeeks Translucent Blue PETG, X and Y flags in Black eSun PETG (100 percent infill)