diff --git a/ObsoleteFiles.inc b/ObsoleteFiles.inc
--- a/ObsoleteFiles.inc
+++ b/ObsoleteFiles.inc
@@ -51,6 +51,9 @@
 #   xargs -n1 | sort | uniq -d;
 # done
 
+# 20250612: remove error-only varargs.h
+OLD_FILES+=usr/include/varargs.h
+
 # 20250521: don't install zoneinfo version
 OLD_FILES+=usr/share/zoneinfo/version
 
diff --git a/include/Makefile b/include/Makefile
--- a/include/Makefile
+++ b/include/Makefile
@@ -33,7 +33,7 @@
 	stdnoreturn.h stdio.h stdlib.h string.h stringlist.h \
 	strings.h sysexits.h tar.h termios.h tgmath.h \
 	time.h timeconv.h timers.h ttyent.h \
-	uchar.h ulimit.h unistd.h utime.h utmpx.h uuid.h varargs.h \
+	uchar.h ulimit.h unistd.h utime.h utmpx.h uuid.h \
 	wchar.h wctype.h wordexp.h xlocale.h
 
 .PATH: ${SRCTOP}/contrib/libc-vis
diff --git a/include/varargs.h b/include/varargs.h
deleted file mode 100644
--- a/include/varargs.h
+++ /dev/null
@@ -1,35 +0,0 @@
-/*-
- * SPDX-License-Identifier: BSD-2-Clause
- *
- * Copyright (c) 2003 Alexander Kabaev
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- * 1. Redistributions of source code must retain the above copyright
- *    notice, this list of conditions and the following disclaimer.
- * 2. Redistributions in binary form must reproduce the above copyright
- *    notice, this list of conditions and the following disclaimer in the
- *    documentation and/or other materials provided with the distribution.
- *
- * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
- * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
- * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
- * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
- * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
- * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
- * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
- * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
- * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- */
-
-#ifndef _VARARGS_H_
-#define	_VARARGS_H_
-
-#error "<varargs.h> is obsolete."
-#error "Change your code to use <stdarg.h> instead."
-
-#endif /* !_VARARGS_H_ */