> Kawa has make-temporary-file, which takes a format:
> https://www.gnu.org/software/kawa/Files.html#idm139913596085696
>
> (The note about race conditions is obsolete and will be removed.)

OK, it's a wrapper around this:
<https://docs.oracle.com/javase/7/docs/api/java/io/File.html#createTempFile(java.lang.String,%20java.lang.String,%20java.io.File)>