--- /dev/null
+#!/bin/sh
+
+set -e
+
+# functions already in src/proxmox-acme
+PRESENT=$(awk 'BEGIN{ORS="|";} /^_/{ gsub(/\(\) {/, ""); print $0}' \
+ ../proxmox-acme | sed -r 's/\|$//')
+
+# functions defined in all plugins
+LOCAL=$(awk 'BEGIN{ORS="|";} /^_/{ gsub(/\(\) {/, ""); print $0}' \
+ ../acme.sh/dnsapi/dns*.sh | sed -r 's/\|$//')
+
+grep -P '\b_[a-zA-Z0-9_-]+ ' ../acme.sh/dnsapi/dns_*sh | \
+ grep -Ev "$PRESENT|$LOCAL|\b_[a-zA-Z0-9_-]+=|^../acme.sh/dnsapi/.*sh: *#"