It doesn’t launch the new binary at all. When the current process wants to create a new process, instead of doing fork+exec (which launches the new binary and wreaks havoc because versions now don’t match), it simply tells the ForkServer (a different process running the old binary) to fork (split) itself.

Chromium also does this; they call their equivalent to ForkServer the zygote process and this article explains it really well.

All external links from news.itsfoss.com articles have that ref parameter added. For example, see the links in this article about the Danish ministry that is switching to LibreOffice.

Edit: This is apparently something that the CMS they use, Ghost, does by default.