Lidl music stand corner support

The cheap music stands sold by Lidl have an extension to support wide sheet music parts. Unfortunately that extension bar tends to sag, thus not continuing to offer support. This T-shaped piece holds the extension bar in the correct (horizontal position).
The stl file is for the right-hand side. You need to print one mirrored along the X axis to generate the left-hand side. Use black abs to match the black color of the music stand.
Update: fixed a detail in the center, and added the Google Ske