Agama, wow, thank you SO much for the suggestions. I will squirrel them away somewhere for when I'm ready to dig in further.
I don't have much background in programming, just self-taught with vba, and a bit of SQL, and such, and recently with Sigil, have been picking up the HTML/CSS stuff. But I do tend to be pretty adventurous, and have registered for a course in the fundamentals of programming that's based on python. So I have great hopes that it will give the grounding I need to get somewhere with contributing to the plugin bonanza.
Again, thanks - it's nice to get the encouragement!