As character names:

U+2359 APL FUNCTIONAL SYMBOL DELTA UNDERBAR 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 153, hex 0x99, octal \231, binary 10011001
This is continuation byte 2, expecting 0 more.

U+2359	APL FUNCTIONAL SYMBOL DELTA UNDERBAR