The srcipt comes as an .exe file?? mmm i pass :P
Yes. It was so when I've downloaded it first time about 6 years ago and it is so now. Actually it adds the Wahooney Tools - ViewportAutoSnap.ms script to C:\Program Files\Autodesk\3ds Max 2021\scripts\Startup folder. I don't know is there something but that file added to somewhere - I didn't find anything, but I can share the script file here and you can try to place it in Startup folder and see if it works or not, if you want.