How to inject metadata for first-order ambisonics with head-locked stereo?

[Boscop]

How to inject metadata for first-order ambisonics with head-locked stereo?

Here under "Minimum requirements for spatial audio" list item 5 it says:

Supported First Order Ambisonics (FOA) with Head-Locked Stereo format:
W, Y, Z, X, L, R as a 6-channel audio track in your uploaded file, sample rate: 48 kHz

Which arguments should I pass to the injector script?
Assuming the video already contains a 6-channel audio track in that channel ordering.

---

The semantics section says

head_locked_stereo is a 1-bit flag used to indicate that the stored audio track contains head-locked stereo audio in addition to ambisonics audio.

BUT: This flag is not even mentioned in the syntax!

And it doesn't say which args to pass to the injector script, to set this flag in the metadata..

Does anyone know? :)