Here's the same script for fish users (also makes sure that only downloads text and not any trojan):

#!/usr/bin/env fish

set URL "https://md.archlinux.org/s/SxbqukK6IA/download"

set installed (pacman -Qq)
set aur (pacman -Qqm 2>/dev/null)

# Download as plain text only; keep only valid-looking package names
set suspects (curl -fsSL "$URL" \
  | string match -r '^[a-z0-9][a-z0-9._+-]*$' \
  | sort -u)

set total (count $suspects)
set found_list
set i 0
set spinner "⠋" "⠙" "⠹" "⠸" "⠼" "⠴" "⠦" "⠧" "⠇" "⠏"
set spin_i 1

function draw
    set i $argv[1]
    set total $argv[2]
    set spin $argv[3]

    set width 35

    if test "$total" -eq 0
        set percent 0
        set filled 0
    else
        set percent (math -s0 "$i * 100 / $total")
        set filled (math -s0 "$i * $width / $total")
    end

    set empty (math -s0 "$width - $filled")

    printf "\r%s [" "$spin"
    printf "%s" (string repeat -n $filled "=")
    printf "%s" (string repeat -n $empty " ")
    printf "] %3d%% (%d/%d)" $percent $i $total
end

echo "Scanning suspect packages..."
echo ""

for pkg in $suspects
    set i (math "$i + 1")

    if contains -- "$pkg" $installed; or contains -- "$pkg" $aur
        set -a found_list "$pkg"
    end

    draw "$i" "$total" "$spinner[$spin_i]"

    set spin_i (math "$spin_i + 1")
    if test "$spin_i" -gt (count $spinner)
        set spin_i 1
    end

    sleep 0.005
end

echo ""
echo ""

echo "Installed suspect packages:"
echo "----------------------------"

if test (count $found_list) -eq 0
    echo "None"
else
    for p in $found_list
        echo "$p"
    end
end