Yes, I had read the topic, but it says nothing about Giteki mark.
There are many cellphones in the world without the mark and some people use it illegally.
(I don’t mean the article recommends to use it illegally. The article just introduces an interesting and technical news from USA.)
Gihyo(技評) is short of Gijutsu Hyoron Sha(技術評論社=Technology Critic Company).
A so-so big publisher selling the tech books. (Private company)
Giteki(技適) is short for Gijutsu Tekigou Kijun Shoumei (技術基準適合証明=Certification of Conformance to Technical Standards).
A standard managed by the Japanese national government. (Public Rule)
Both Gi (技) comes from the word Gijutsu (技術=Technology).
BTW, I have written a few books / magazine article from Gihyo