This is the flange for the BLTouch Auto Leveling Sensor (see link below) that can be used to mounting the sensor. The OpenSCAD file is included so this can be used to design your own mounting system.
The STL files aren't very useful but are included to show the design variants. The OpenSCAD is the useful piece of work for this thing.
There are a couple variations. The first is the exact shape of the BLTouch mounting flange. There is minimal surface area to mount this flange, so the second variation is a "rectangular" flange. There is an optional "bracket" that can be added to either flange type.
The flange variation, bracket placement, bracket size, etc are all set by parameters. There are no holes in the mounting brackets because I didn't know how others will use this. They will need to be added as necessary, The flange is created as a module and I believe the code is fairly easy to understand. Comment if you have questions.