Here we provide a little bit of documentation about the asset HZMBC that is implemented on the Horizon platform (as asset ID 2067433651907705126).
HZMBC is the Galactic Milieu's "big seven" currency MBC (Martian BotCoin), as implemented on the Horizon platform.
The currency consists of only 21,000,000 coins, as it was originally inspired by BiTCoin. Unfortunately we were technically unable to create it as a currency on Horizon so had to create it as an asset. Some glitch ended up having it named MtnBotCoin when it was actually created on the platform, hence the note that it is "also known as" MtnBotCoin.
The issuing account created all 21,000,000 so that if all of the coins get transfered to the Horizon platform the platform is ready to handle them all. However, any that remain in the issuing account are taken as not having been issued on the Horizon platform. They probably mostly remain on the Digitalis Open Transactions server.
Any MBC that have been moved to the Horizon platform are transfered out of the issuing account, so that the amount by which the issuing account is short of 21,000,000 is the number of MBC that has actually been issued onto the Horizon platform.
Some potentially useful tables and plots are online at http://galaxies.mygamesonline.org/digitalisassets.html