Header/preface definitions in ox-taskjuggler?

[John Hendy <jw.hendy@gmail.com>]

I note that the defaults for a taskjuggler export in Org are as
follows, with taskjuggler syntax and related org variable definitions
listed.

Project tj syntax: project [<id>] <name> [<version>] <interval2> [{
<attributes> }]

Org defaults:
- id: nil
- name: name of heading tagged with org-taskjuggler-project-tag
- version: org-taskjugler-default-project-version
- interval2: SCHEDULED: <date> + org-default-project-duration

For some reason the default global properties are defined as:

shift s40 "Part time shift" {
  workinghours wed, thu, fri off
}

I'm interpreting this to mean W-F are "off days"? If that's the
correct interpretation per the syntax, I don't understand why this
would be the default definition. Then again, perhaps it's just a
definition and you have to apply it to a task to use it?
- http://www.taskjuggler.org/tj3/manual/workinghours.shift.html

In any case, this is the one that's goofing me up. The first task gets
the following lines prepended to it:

task task1 "task1" {
  purge allocate