To answer your original question with a technical answer, the "flink" and "blink" you were questioning describe a
Forward
Link and
Backward
Link in a
linked list. Lots of structures in Windows use linked lists to keep track of things, especially the memory manager, but the FLink and the BLink are ways of validating that a linked list is still valid, what's around, etc. It can be useful for debugging, but that's what it means.