This is a modified x-axis limit switch mounting block that is needed for the Ender 5 Plus with MGN12H linear rails and the Micro Swiss NG direct drive extruder (M3204). See the original creator here: (https://www.thingiverse.com/thing:3960105)

The original creator shows the limit switch on its stock mounting plate which is then attached to this block. This appears to work fine with the stock extruder or with the regular Micro Swiss direct drive extruder, but it does not work with the NG extruder. It causes the endstop to collide with the fan shroud, so if you're using the NG extruder the limit switch needs to be mounted directly to this block instead. You will also have to remove the plastic cover on the switch itself for clearance. For any other extruder, it can be used as it was originally designed.