Eh .. the commands suggested there include ones that remove all flatpaks while missing some other opportunities for cleaning.
I might even dare to say maclean does a better job;
Click to see the isolated flatpak function
## Flatpak Data ##
_mc_flatdata() {
if command -v flatpak >/dev/null 2>&1; then
if _mc_confirm "Clean old and disabled Flatpak runtimes and SDKs"; then
local _mc_quicksums _mc_quicksums2 _mc_diff
_mc_calcsiz _mc_quicksums "$HOME/.local/share/flatpak" /etc/flatpak/installations.d /var/lib/flatpak
if [[ -d "$HOME/.local/share/flatpak" ]]; then
if _mc_confirm "Clean user flatpaks"; then
flatpak uninstall --unused --user
flatpak repair --user
else
printf "Skipped\n"
fi
fi
if [[ -d /etc/flatpak/installations.d || -d /var/lib/flatpak ]]; then
if _mc_confirm "Clean system flatpaks"; then
flatpak uninstall --unused
_mc_sudo_wrap flatpak repair
else
printf "Skipped\n"
fi
fi
if [[ -d "$HOME/.var/app" ]]; then
if _mc_confirm "Clear flatpak application data"; then
flatpak uninstall --delete-data
else
printf "Skipped\n"
fi
fi
if compgen -G /var/tmp/flatpak-cache-* >/dev/null 2>&1; then
if _mc_confirm "Clear flatpak cache"; then
_mc_rm_safer sudo /var/tmp/flatpak-cache-*
else
printf "Skipped\n"
fi
fi
_mc_calcsiz _mc_quicksums2 "$HOME/.local/share/flatpak" /etc/flatpak/installations.d /var/lib/flatpak
printf "Done\n"
_mc_calcdif
else
printf "Skipped\n"
fi
elif [[ -d "$HOME/.cache/flatpak" || -d "$HOME/.var/app" || -d /var/lib/flatpak ]] || compgen -G "$HOME/.local/share/flatpak/db/"* >/dev/null 2>&1 || compgen -G "/var/tmp/flatpak-cache-"* >/dev/null 2>&1; then
if _mc_confirm "Clean up ALL Flatpak application data"; then
local _mc_quicksums _mc_quicksums2 _mc_diff
_mc_calcsiz _mc_quicksums "$HOME/.var/app" "$HOME/.local/share/flatpak" "$HOME/.cache/flatpak" /etc/flatpak/installations.d /var/lib/flatpak
_mc_rm_safer sudo "$HOME/.var/app" "$HOME/.local/share/flatpak" "$HOME/.cache/flatpak" /etc/flatpak/installations.d /var/lib/flatpak /var/tmp/flatpak-cache-*
_mc_calcsiz _mc_quicksums2 "$HOME/.var/app" "$HOME/.local/share/flatpak" "$HOME/.cache/flatpak" /etc/flatpak/installations.d /var/lib/flatpak
printf "Done\n"
_mc_calcdif
else
printf "Skipped\n"
fi
fi
}
( And its in the AUR now as maclean-git )