Knowledge is a type of system that records long-term findings for later use. Rather than trying to remember everything you’ve learned, you can document and organise it in an optimised way, and possibly even share it, which is the intention of the JSM’s knowledge section.
Knowledge is best written in a generic way, as it isn’t supposed to change frequently. Processes, trackers and tools should all be very personal and unique, but having more generalised knowledge makes it easier to maintain, more reusable, and better in the long term.