"This is a Linux-native reimplementation inspired by darrylmorley/whatcable"
https://github.com/nedrichards/whatcable-linux
But (hazard guess) it comes with a headless CLI binary (no GUI libraries needed) so probably could be ported to Linux (easily with an LLM?)
There is also https://github.com/Zetaphor/whatcable-linux (if you want a KDE UI rather than Gnome) and https://github.com/vzaliva/whatcable-linux-cli (a fork of the KDE repo, but only leaves the CLI tool).
WhatKable was right there!