What does the following structure of projects on github usually mean?

Question

GitHub

From time to time I go to some repos on github and often observe a structure like bin, src, tests, etc. I would like to know if it is accepted somewhere that this is how the folders should be called, or do you need to use some kind of tool that generates them?
tests - it's clear that unit tests are here
src - as I understand it, this is where all the project code written by the repository's author lies?
bin - console commands? vendor
- dependencies that the author pulled up with the composer