JKD was supposed to be a martial art that adapted the best techniques from other martial arts. e.g. "have no style" because your style is constantly adapting.
After Lee died, JKD broke into two camps:
1. "We should only teach what Lee taught us and no more. e.g. the techniques he taught us are the core techniques."
2. "Lee taught us to be constantly adapting from other martial arts so there is no list of core techniques."
I've always loved this story as it highlights how humans have essentially two reactions to change: embracing it or fearing it.