Hi Neon,
many thanks for your kind report.
Mike and me were indeed pleased to have met you 
That plastic thingy is the Strida frame clip (Part nr.: ST-4219), it will help you to save the Achilles’ heel of your Strida, the rear joint.
Here’s more info and also images of a folded Strida:
https://stridacanada.ca/strida-bikes-rear-hinge-explained
What you saw was an orange “Cyclehoop” stand,
Cyclehoop Stand for the Strida
not that cheap, but good quality and very heavy.
For me personally disappointing that it doesn’t fit 18" wheels.
You’re always welcome, hope to see you again some day 
Cheers,
Chris