As character names:

U+27E6 MATHEMATICAL LEFT WHITE SQUARE BRACKET 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 159, hex 0x9F, octal \237, binary 10011111
This is continuation byte 1, expecting 1 more.

Byte number 3 is decimal 166, hex 0xA6, octal \246, binary 10100110
This is continuation byte 2, expecting 0 more.

U+27E6	MATHEMATICAL LEFT WHITE SQUARE BRACKET
	= z notation left bag bracket
	x (left white square bracket - 301A)