How to use methods()?

Question

R> library(hexbin)
R> methods(plot)
 [1] plot,ANY,ANY-method        plot,hexbin,missing-method plot.acf*                  plot.data.frame*
 [5] plot.decomposed.ts*        plot.default               plot.dendrogram*           plot.density*
 [9] plot.ecdf                  plot.factor*               plot.formula*              plot.function
[13] plot.hclust*               plot.histogram*            plot.HoltWinters*          plot.isoreg*
[17] plot.lm*                   plot.medpolish*            plot.mlm*                  plot.ppr*
[21] plot.prcomp*               plot.princomp*             plot.profile.nls*          plot.raster*
[25] plot.shingle*              plot.spec*                 plot.stepfun               plot.stl*
[29] plot.table*                plot.trellis*              plot.ts                    plot.tskernel*
[33] plot.TukeyHSD*
see '?methods' for accessing help and source code

I am not sure what plot,hexbin,missing-method means, as other methods contains "." instead of ",". Could anybody explain what it means?

But I want to see how the plot for hexbin is defined. How to access it?