Meditation and mindfulness explained as cognitive mechanics

Had a conversation with a friend about meditation last night and remembered my notes from researching how it works, how thoughts arise, why do I get into loops, etc. I found a very good structure in Theravāda Buddhism, but I struggled with the terminology and mapping it to my rationalistic model of thinking. This resulted in a very fruitful session with ChatGPT some time ago, and then a good set of notes, that actually helped me understand whats happening. Now I've dusted this up and put it together to share with friends, hope it is useful for somebody.