diff --git a/src/var.c b/src/var.c
index 87f33af282..94d79695ac 100644
--- a/src/var.c
+++ b/src/var.c
@@ -362,6 +362,7 @@ static ParameterError addvariable(const char *name,
   p = calloc(1, sizeof(struct tool_var) + nlen);
   if(p) {
     memcpy(p->name, name, nlen);
+    /* the null termination byte is already present from above */
 
     p->content = contalloc ? content : memdup0(content, clen);
     if(p->content) {