As character names:

U+2370 APL FUNCTIONAL SYMBOL QUAD QUESTION character (⍰)

As raw characters:

⍰

As a string of HTML entities:

⍰

Decoder output:

Byte number 1 is decimal 226, hex 0xE2, octal \342, binary 11100010
This is the first byte of a 3 byte sequence.

Byte number 2 is decimal 141, hex 0x8D, octal \215, binary 10001101
This is continuation byte 1, expecting 1 more.

Byte number 3 is decimal 176, hex 0xB0, octal \260, binary 10110000
This is continuation byte 2, expecting 0 more.

U+2370	APL FUNCTIONAL SYMBOL QUAD QUESTION
	x (uncertainty sign - 2BD1)