diff --git a/tool/build/findpe.c b/tool/build/findpe.c
new file mode 100644
index 000000000..548ea288a
--- /dev/null
+++ b/tool/build/findpe.c
@@ -0,0 +1,58 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│ vi: set et ft=c ts=2 sts=2 sw=2 fenc=utf-8                               :vi │
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2023 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ Permission to use, copy, modify, and/or distribute this software for         │
+│ any purpose with or without fee is hereby granted, provided that the         │
+│ above copyright notice and this permission notice appear in all copies.      │
+│                                                                              │
+│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL                │
+│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED                │
+│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE             │
+│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL         │
+│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR        │
+│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER               │
+│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
+│ PERFORMANCE OF THIS SOFTWARE.                                                │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/calls/calls.h"
+#include "libc/runtime/runtime.h"
+#include "libc/stdio/ftw.h"
+#include "libc/stdio/stdio.h"
+#include "libc/sysv/consts/o.h"
+
+static int OnFile(const char *fpath, const struct stat *st, int typeflag,
+                  struct FTW *ftwbuf) {
+  if (typeflag == FTW_F) {
+    char buf[2] = {0};
+    int fd = open(fpath, O_RDONLY);
+    if (fd != -1) {
+      pread(fd, buf, 2, 0);
+      close(fd);
+      if (buf[0] == 'M' && buf[1] == 'Z') {
+        tinyprint(1, fpath, "\n", NULL);
+      }
+    } else {
+      perror(fpath);
+    }
+  }
+  return 0;
+}
+
+static void HandleArg(const char *path) {
+  if (nftw(path, OnFile, 128, FTW_PHYS | FTW_DEPTH)) {
+    perror(path);
+    exit(1);
+  }
+}
+
+int main(int argc, char *argv[]) {
+  if (argc <= 1) {
+    HandleArg(".");
+  } else {
+    for (int i = 1; i < argc; ++i) {
+      HandleArg(argv[i]);
+    }
+  }
+}