As character names:

U+301A LEFT WHITE SQUARE BRACKET character (〚)

As raw characters:

〚

As a string of HTML entities:

〚

Decoder output:

Byte number 1 is decimal 227, hex 0xE3, octal \343, binary 11100011
This is the first byte of a 3 byte sequence.

Byte number 2 is decimal 128, hex 0x80, octal \200, binary 10000000
This is continuation byte 1, expecting 1 more.

Byte number 3 is decimal 154, hex 0x9A, octal \232, binary 10011010
This is continuation byte 2, expecting 0 more.

U+301A	LEFT WHITE SQUARE BRACKET
	= left abstract syntax bracket
	x (mathematical left white square bracket - 27E6)