it will generally start with a 35, which is unused as a country calling code
It's "unused" because several country codes start with 35: Ireland, Portugal, Luxembourg, Iceland... (This doesn't mean that phones are actually manufactured there... I have a phone with an IMEI starting in 354 and it's definitely not manufactured in Iceland...)
Yeah, they seem to be confusing that with IMSIs or ICCIDs, which are indeed namespaced by mobile country code and international calling code respectively.
Based on what other commenters have already pointed out, this seems to be a quite sloppily researched article.
This is interesting - I hadn't noticed this, but my Chinese (Xiaomi) phone indeed has an IMEI starting with 86, which is China's dialling code. Perhaps a coincidence.
The ICCID starts 8944 - not sure of the significance of the 89, but 44 is the UK, where my SIM card (and me) comes from.
