Can someone please help me understand what "barefoot notes" means?
This reminds me of the barefoot doctor in Mao's China. In a similar vein barefoot notes probably refers to them being basic and sketchy.
I've never heard the term "barefoot notes". The other comment was not intended to criticize you, just to show that he's never heard of it either. It does show up in a web search, but there is no consistent meaning. My best guess is that it is just another untranslatable English phrase, having as many meanings as there are people using it.
If I had to guess, I'd say that it described very informal notes or thoughts about things - going barefoot in this country is very informal.