About 8 years ago I created a GIMP plugin to read Terry Davis' (creator of TempleOS) custom image files to convert them to bitmaps, and vice-versa. I didn't know anything about the .bmp file format, or how to create a GIMP plugin. I wrote a blog post detailing the creation and discovery process. I contacted Terry Davis throughout to ask for help and feedback, and he was helpful and appreciative. It was interesting and rewarding to interact with him and learn a bit about his operating system. I was sad when he passed.

https://michaelbarlow.com.au/gra-plugin/