# Assuming you have UnicodeChecker’s Spotlight support installed on your Mac,
# you can use mdfind to find unicode characters on your machine.
# A bit of command line wrangling later you may find the character names.

mdfind roman numeral uccharacter | xargs -I FILENAME -L 1 sh -c 'plutil -convert xml1 -o - "FILENAME" | xpath "//string[preceding-sibling::key/text()=\"name\"]/text()"; echo ""' 2>/dev/null