As character names:

U+1FBC4 NEGATIVE SQUARED QUESTION MARK character (🯄)

As raw characters:

🯄

As a string of HTML entities:

🯄

Decoder output:

Byte number 1 is decimal 240, hex 0xF0, octal \360, binary 11110000
This is the first byte of a 4 byte sequence.

Byte number 2 is decimal 159, hex 0x9F, octal \237, binary 10011111
This is continuation byte 1, expecting 2 more.

Byte number 3 is decimal 175, hex 0xAF, octal \257, binary 10101111
This is continuation byte 2, expecting 1 more.

Byte number 4 is decimal 132, hex 0x84, octal \204, binary 10000100
This is continuation byte 3, expecting 0 more.

U+1FBC4	NEGATIVE SQUARED QUESTION MARK
	* glyph does not necessarily extend to the edges of the character cell
	x (question mark - 003F)
	x (uncertainty sign - 2BD1)
	x (replacement character - FFFD)