Not sure exactly what it is called, but you can see it in the below image.
I was testing my front brake (running new cable and housing), when SNAP, the cable pops right out of the doo-hickie that it routes through in the lever.
In the following image, the cable end is still in the larger hole. However, just a little bit more pressure, and it pops right out.
1) Cable housing is too long. (Here is my cable routing.)
2) Cable router is backwards (channel should face up when properly installed, rather than down).
3) Hood needs trimmed just below the lever, as it touches.
4) I am experiencing a previously unknown phenomenon.