Originally Posted by
LupineChemist
It's an EU ID card that they call a "passport card" so people don't go nuts about ID cards. It's functionally the same as any other EU ID card within the EU. As it's an Irish ID card, it's also valid in the UK which is particular to Ireland rather than any other EU country.
I don't disagree with the sentiment here, but technically it is a different class of document according to the ICAO standards.
The MRZ of a national ID card starts with the letters ID, the MRZ of an Irish passport card (and other passport cards, including the USA) begins with IP.
On searching for references here it seems there may be changes to the MRZ of typical passports from 2026 to make use of the second character, allowing for the MRZ to more readily identify non-standard passports such as diplomatic etc.