I am not sure what they are attempting with this but rumor has it that Toyota is working on a 2021 Mirai that will run on cow poop.
I have a lot of questions when it comes to something like this but if it is possible, this is something that can impact the future of cars.
Toyota has been interested in cow manure for several years. In 2017, the Japanese company announced with Shell that they were building a power plant in Long Beach, California that would capture methane gas from dairy cattle manure and convert it into water, electricity, and hydrogen. The companies went ahead with their project, called Tri-Gen, as a "hydrogen-truck refueling station" in 2018.
Nothing really new - just sounds fantastical. Cow poop is just another source for feedstock for hydrogen gas generation. Doesn't mean the car will run directly on manure, just like biomass and other similar sources, a factory captures the methane gas from the material and converts it to hydrogen - usually from a steam reforming process (lots of heat + nickel catalyst, splits methane into hydrogen and carbon monoxide). Most of the hydrogen in the world is manufactured in this process, but is extremely cost prohibitive unless generated at scale. There is also athermal reforming, but that also has some cost/gas generation issues that have to be addressed. Reformer cells could be a possibility - basically shrinks the factory into a space that could fit in the car, but you'd have to overcome a ton of engineering issues - right now those are just engineering thoughts / lab prototypes. Thermodynamic efficiency and dealing with waste contaminants is major issue with those.
I wonder, do you figure having wind turbines or solar panels doing it in their “off-times” (when the grid doesn't need the power) would reduce the cost of providing hydrogen? Seems to me we have a methane problem re global warming, and our antiquated grid can't spin up and shut down coal, natural gas, or nuclear plants easily, so the renewables are often shut off; this could resolve both issues.