Shade umbrellas often break at the hinge point where the stay is supported. This is a splint to repair such a break.
Umbrellas can get quite hot and PETG will soften, so a higher temperature material like ASA needs to be used.
At the time of publishing, the different expansion coefficients of the ASA and the underlying steel stays made the splint split during storage in the winter. If you have a very good idea to resolve that, please share it for the source code on Github.
Source code is at: https://github.com/geru/3d-scad-umbrellasplint
The author marked this model as their own original creation.