This is a simple music stand for the Alesis Q Mini compact MIDI controller; the idea is that you print two or three of these, clip the controller into them, and prop music up between the controller and the sloped back of the stand. There are two variants, one at a relatively shallow angle that works well for hardbound hymnals and songbooks, and one at a relatively steep angle that works well for thinner softbound music books and loose papers. (A single one can, as pictured, just barely work to hold up a hardbound book.)
The original model is publicly available on Onshape, and is extensively parameterized. As a “Public Document” created by a "Free Plan User" after August 7, 2018, the applicable copyright license may be found in Onshape's Terms of Use; the language there closely resembles the X11 ("MIT") license. You'll also see my music stand for the Nektar SE49 there, because this originated as a derivative of that.
The author remixed this model.
Remodeled to fit the Alesis Q Mini instead of the Nektar SE49.