Cofeiini

I don't usually use networking in C or C++, so I can't say for sure. But I did I find this quote that might explain it:

The reasons for having both 16 and 32 bit functions is that IP and TCP headers use a mix of 16-bit fields like port numbers along with 32-bit IPv4 addresses.

If I understood correctly, the difference is that the returned value is either uint16_t or uint32_t. Otherwise they look the same based on the headers and documentation.

I get the same errors about descriptor, but no mention of mlt or missing libraries.
I tried the flatpak version and that seems to be working.

There should be a config file in ~/.config/MangoHud (you can check more details in the GitHub page https://github.com/flightlessmango/MangoHud#hud-configuration).

By adding frametime=0 to the config file, you should be able to remove the frametime measurement from the FPS display.

It's maintained on GitHub, so you might be able to manually install it or find a package for it in your package manager. At least on Arch you can install gnome-shell-extension-ddterm-git from the AUR.

I use ddterm, which is pretty much the only remaining drop-down terminal extension. https://extensions.gnome.org/extension/3780/ddterm/