The cable stop? Where the housing stops. bare wire starts, still gets a fair pull.
I run a ridged fork and have used various headset and neck anchors. The through the headset or under pull the headset down.
This type pulls the headset foreward. a Trek in my basement w\ this has had collar of the headset loosen right up.
If you brake the fork pulls backward.
I was told by an informed LBS owner the 'catch' was to be located closest to the centerpull for max power. Maybe similar to 700 road bike brakes mounted in the same spot. I think i'm borrowing bmx ideas again.
My LBS friend also nixed the frame anchor I posted.