See also the related feature request 1890701!
.port file is auto-generated by Save IDE; it is a very simple file, see example:
<PORT>
<APPLICATION filename="Turntable.save"/>
<ENVIRONMENT filename="env.xml"/>
</PORT>
...
"Turntable.save" is taken from the model, but "env.xml" appears hard-coded. It would be nice if the user was not forced to name the environment model env.xml but could choose any name.
...
PS. Yes, a perfectly working "fix" is to simlpy write a custom .port file with the wanted ENVIRONMENT filename. And renaming this file to .save solves the 1890701 request as well. But every time one re-generates the model the "useless" .port file appears.