Contents of the tweet:

1. Announcement for Hardware reservations and prices expected between Jun 22 - Jun 30
2. Reviewers are actively receiving Steam Machine and Steam Frame units (see enclosed photos)
3. Steam Machine comes with a Steam Controller, 2 mounting brackets and a Steam Machine in a box.
4. There are separate boxes for faceplates (unsure if shipping by default)
5. Creators embargo seems to be due to lift on Hardware reviews after Jun 23
6. Unclear whether Steam Machine and Frame are launching simultaneously, likely

However in a subtweet they also write:

Steam Machine seems to be before frame, but the wait for Frame isn’t long 👍