That's most likely made for the Hong Kong market, where lots of PC-Engines / Famicoms were sold on export.
+1
Hong Kong was under British rule and used our PAL TV standard.
Because of our connection with the country most of the imported PC Engine and Mega Drive stuff came via Hong Kong back in the day.
yes, tv terrestial tv in Hk is pal, but most tv since the early 90s or even late 80's are multi standard tv which accepts ntsc via composite video or s video, a few even scart ( most likely sony during mid 90s) which could be rgb enabled but this quite rare