Mosaic was not the first browser (that was nexus, renamed thus when it's original name WorldWireWeb created some confusion)

Mosaic the company indeed. Tried to monetize in the server by giving away the browser.

However CERN also provided a free mit licensed Server, CERN httpd

https://en.m.wikipedia.org/wiki/CERN_httpd#:~:text=CERN%20ht....

And it was not simply "served via TCP socket", it was served via a protocol that was similar to but simpler as another protocol, http vs ftp.