Thanks for sharing that, pfren. 14.f5 is clearly stronger than 14.Ra2, which Watson gives. More to the point than the h2-h4-h5 plan. I am impressed with how white's initiative persists, even with diminished material. A lot for me to chew on here.
Old fox Hertneck has played a more viable line in a rapid game:
Black's position is not terribly pleasant, but at least it does not lose by force, which is the case for the other line after 14.f5.
The French Hertneck is currently in grave trouble.
The nice move 14.f5!! which gives white a huge positional advantage was found by 3-times correspondence WC Aleksandr Dronov. Since his introduction back in 2015, the OTB score isn't very pleasant for Black: Zero wins, one draw, and 18 losses (5.2%).