ADB (Android) output of ls -l /dev/block/xxxxx

Question

linux

I must say right away that there is little experience with linux, even less in the field of Android firmware. So, interested in what is contained in / dev / block? (Google shows links with some actions on this, but not a description, so I ask you to poke your nose or tell me in a nutshell). I would also like to know what the highlighted number means (when output, for example, ls -l / in this place the size of the files):

Answer 1

en.wikipedia.org/wiki/Device_file
Read for general understanding