Jeff Jump is a skip in Dark Souls II in which the player performs a precise jump onto the bridge in the gutter. It saves
~13 seconds in runs which require jumping across for the branch and a bit less in other runs which do not require the branch.
It is named after runner JeffTheBigLizard, who first popularized the jump.
The jump can be seen at 1:28 in this tutorial:
Jeff Jump Tutorial by JeffTheBigLizard