*** John Goerzen [2021-01-15 15:38]:
>I had thought that it should be on the same disk, to facilitate a quick rename.

NewTmpFile is used for what you are describing. Actually it is not for
temporary storage, but for atomic file writing/renaming.
But temporary file for nncp-exec/"nncp-file -" holds really temporary
data, used for encrypted packet preparation.

>Just to confirm -- everything written to /tmp is encrypted, right?

Everything that written to the file in $TMPDIR, if more precisely.
Yes, it is encrypted with the random ephemeral key, exactly to be able
to place it anywhere you wish without fear.

-- 
Sergey Matveev (http://www.stargrave.org/)
OpenPGP: CF60 E89A 5923 1E76 E263  6422 AE1A 8109 E498 57EF