List Gutenberg languages from ZF config

list_gutenberg_languages.sh

#!/usr/bin/env bash
BASE="https://api.farm.openzim.org/v2"
LIMIT=100

for EP in recipes schedules; do
  SKIP=0; out=""
  while :; do
    page=$(curl -s "$BASE/$EP?name=gutenberg&limit=$LIMIT&skip=$SKIP")
    if ! jq -e '.items' >/dev/null 2>&1 <<<"$page"; then
      echo "[$EP] unexpected response:" >&2
      echo "$page" | head -c 500 >&2; echo >&2
      continue 2
    fi
    out+=$(jq -r '.items[].name' <<<"$page")$'\n'
    count=$(jq -r '.meta.count // 0' <<<"$page")
    SKIP=$((SKIP + LIMIT))
    [ "$SKIP" -ge "$count" ] && break
  done
  printf '%s' "$out" \
    | sed -nE 's/^gutenberg_([a-z]{2,3})_.*/\1/p' \
    | sort -u | paste -sd, -
  exit 0
done
echo "Neither endpoint worked; see responses above." >&2