I was planning to change them at 30k.
I felt my Focus RS benefitted from new plugs, specifically these Ruthenium, so was going to do the same for the Ranger.
I have 4 NGK 90495 "Ruthenium HX High Ignitability" spark plugs. Per RockAuto these are the stock spec for the 5G Ranger. I purchased these last year, but later traded my Ranger for another vehicle.
They are new in box, never installed. But they are free, so "as-is".
If you live near by...
To follow up, dealer said the grid was bad. The traces aren't damaged nor are the tabs. Such a failure they say is quite unusual.
It is not repairable, the whole rear window needs to be replaced. ~$1500 part+labor. I'm 3 months out of 3/36 but it is covered under my Ford extended warranty...
I bought an assortment from Amazon. 6.3mm (1/4") fits perfectly. You can find both the OEM style with the screw or just a pin you need to pry out.
Glad I'm not the only one who made that mistake!