When you open a PBM file in a text editor, it looks to be nothing but text - maybe a few codes and some notes, but certainly lots of 1s and 0s.
Mgbe ị mepee faịlụ PBM na nchịkọta ederede, ọ na-ele anya ịbụ ihe ọ bụla ma ọ bụghị ederede - ma eleghị anya koodu ole na ole na ụfọdụ ederede, ma n'ezie nza nke 1s na 0s.