File names, URLs and email address support utf-8 characters and you may want to lower case them in many situations. If the user is trying to search for a string

File names, URLs and email address support utf-8 characters and you may want to lower case them in many situations. If the user is trying to search for a string, they probably want case insensitivity. I don't think it's that rare/weird for people to want localisation to apply when calling toLower.