U+3386 Square Mb

The Wikipedia has the following information about this codepoint:

The megabyte is a multiple of the unit byte for digital information. Its recommended unit symbol is MB. The unit prefix mega is a multiplier of 1000000 (10⁶) in the International System of Units (SI). Therefore, one megabyte is one million bytes of information. This definition has been incorporated into the International System of Quantities.

However, in the computer and information technology fields, two other definitions are used that arose for historical reasons of convenience. A common usage has been to designate one megabyte as 1048576bytes (2²⁰ B), a quantity that conveniently expresses the binary multiples inherent in digital computer memory architectures. However, most standards bodies have deprecated this usage in favor of a set of binary prefixes, in which this quantity is designated by the unit mebibyte (MiB). In one context, the megabyte has been used to mean 1000×1024 (1024000) bytes.