It seems that a someone (authorized tester) unlocked the bootloader using a beta international firmware. I found this topic
@maxant69 there is no official global beta firmware for the pro 5.
How did he get hands on this beta? Meizu claims that the Pro 5 beta global won’t be released before mid of February (the earliest).
In Flyme 5 there is no more international firmware, its called global instead.
Update, lol just heard that it got leaked