@danderson The best part is that U+FEFF was originally intended *solely* as a byte order mark: https://www.unicode.org/versions/Unicode1.0.0/ch03_6.pdf

It was changed to ZWNBSP in Unicode 1.1 <https://www.unicode.org/versions/Unicode1.1.0/ch03.pdf>, and as you might expect, "character that may or may not be removed when it's at the start of a string" has caused no end of issues.