It tells you what the paragraph is going to be about.
An F1 hybrid (or filial 1 hybrid) is the first filial generation of offspring of distinctly different parental types. F1 hybrids are used in genetics, and in selective breeding, where it may appear as F1 crossbreed. The term is sometimes written with a subscript, as F1 hybrid.
The 2016 Ford Fusion Hybrid has a 2.0-liter four-cylinder gasoline engine that works in concert with an electric motor that's powered by a lithium-ion battery pack.