Stellar XboxHD+ source code

Are the project stellar mods open source? I recently bought an OG xbox (1st console in over 14 years) and wanted to do a stellar HDMI mod. I was looking at the screen shots and it looks like the mod only supports Truncate and Bilinear upscalling. I would like to use my own upscalling method/code to achieve a smoother image when desired.

I looked around on their GitHub profile but didn't see any code related to upscalling graphics for the HDMI mod.