This in a mounting bracket for a microswitch in the V-series form factor, described here. (You might be used to referring to these as "full size" microswitches).

This bracket is intended to be glued into a nerf blaster in order to mount acceleration trigger microswitches. Standard practice is to glue such switches into the blaster; this bracket allows the switch to be easily replaceable and to be easily taken in and out while soldering. I'm sure it will have other uses as well.

This is intended for use with a pair of 4-40 screws. The holes turned out just barely too small in my test print - but a 3/32nds drill bit fixed that handily. I've left them at the same size as in the test print because printer tolerances are not always great and it's better to have holes that will probably need a little attention from a drill than holes that may turn out too large.

The "old microswitch bracket" is the version that was printed as a test, which you might have if you downloaded this thing back when it was on thingiverse and had "Untested" in the title; the other .stl and .scad has a few tweaks make after that print.

The entire bracket is parametric and you should have a fairly easy time further tweaking it to suit you needs. Worth noting: the hole in the middle is actually an indent that goes all of the way through the plate. If you set the indent_depth to be less than the plate_thickness, you'll get a solid plate under your switch with an indent in the top.