> CLI tools do not implement auto-complete themselves. What you are seeing are auto-complete scripts for your shell that make network connections.

nit: This is incorrect. Robust auto-complete scripts call the actual program to provide completions.

That is what Flatpak does. It is Flatpak itself that makes the network connections.

https://github.com/flatpak/flatpak/blob/main/completion/flat...

Not that it would make any differencen if it was implemented in Bash seeing as the Bash script is also provided by Flatpak.