What is such an "OpenSource"?

And here, by the way, is an interesting topic of license checks and OpenSource. Can someone share practical experience of interaction, when comrades from a certain department came to you with a check? ...

... and were surprised to find out that you have "what else is Linux like?" On your servers

I anticipate such a quest in my offices in the future, so now we are going to surrender to Microsoft for licensing on the direct route. The rest of the software license is already there, some use freeware, in addition there are several servers on which various Linux distributions are installed, ranging from Altov and ending with Fedora.

And if the licenses for commercial software are carefully prepared and accounted for, then what about OpenSource? How to practically confirm the actual “free” of the program, if the stupid official is not interested and he believes that there should be a license for each program? Is it really so? The absence of claims from the right holder is not a reason for not conducting an inspection. Well, how do you get a corporate mailer "for clarification" out for a week or two?
')
“What kind of Fedora? And where is the license for it? What is the GPL? Yes, I can print it too! License, I ask where? On what basis do you use this program, which company transferred you the rights to it? Why print on this license is not delivered? Where is the contract with this company for use? What does it mean “is developed not by the company, but by the community?”

And it's not just about Linux. Licenses for Firefox, Thunderbird, OpenOffice and other freeware software under Windows where they are distributed?

If someone encountered this in practice, please share your experience.