Specials characters supported by the Roboto font

Character	Image
OBJECT REPLACEMENT CHARACTER (U+FFFC)
REPLACEMENT CHARACTER (U+FFFD)

Count: 2

Character
INTERLINEAR ANNOTATION ANCHOR (U+FFF9)
INTERLINEAR ANNOTATION SEPARATOR (U+FFFA)
INTERLINEAR ANNOTATION TERMINATOR (U+FFFB)

Count: 3