Im guessing they did what looked like a fencing mask so the performers (Im guessing more than one) could see and breath better.
Mike Tirico must not have gotten that in the prep notes. He kept referring to them as the mysterious person.
I found this.
The mysterious torchbearer that appeared in a hooded, masked costume was inspired by a number of characters from French culture: Belphégor, the Iron Mask, the titular character from Phantom of the Opera, Fantomas, Ezio from Assassin's Creed and Arsène Lupin.
https://www.nbcchicago.com/paris-2024-summer-olympics/assassins-creed-who-was-the-masked-torchbearer-at-the-2024-paris-olympics-opening-ceremony/3502147/
Arsène Lupin (French pronunciation: [aʁsɛn lypɛ̃]) is a fictional gentleman thief and master of disguise created in 1905 by French writer Maurice Leblanc. The character was first introduced in a series of short stories serialized in the magazine Je sais tout. The first story, "The Arrest of Arsène Lupin", was published on 15 July 1905.
https://en.wikipedia.org/wiki/Ars%C3%A8ne_Lupin