Bleachbit on ubuntu 18.04 delete rotated logs-what does this do?

Hi I ran bleachbit on ubuntu 18.04 using the command delete 'rotated logs'-it says on the program that this deletes old system logs-what are these old system logs? does bleachbit delete anything important using this command?

also what i want to know is if the bleachbit command 'rotated logs' deletes any other files that are not system logs, say for example internet browsers files such as firefox/tor browser or files needed to use openvpn? thats what i wish to find out