https://trac.torproject.org/projects/tor/wiki/TorRelayGuide#Bridge
On that page they have "Fast exit relays (>=100 MBit/s)" and "MBit/s (Mbps)". MB means megabytes I would think.
bits are not capitalized. It is Mbit/s or more simply Mbps. And tor is primarily a network tool interfacing with network providers and net hardware at network speeds, not a disk storage or memory testing or webhosting (ugh) app, so it's not Bytes or powers of two prefixes. People screw this stuff up all the time. The international standards docs with how to express things correctly have been posted to this list many times.
Feel free to read them and then fix that page.