Basically this token is backed by Hive, its infrastructure as well as the value of the currency.
The main rule for the issuance of this token is Hive's market capitalization, which cannot exceed HBD by 10%, this according to issuance rules.
In general, it works like other assets that have the value of 1USD but with the particularity that to be issued the user commits his Hive in the main ecosystem, so each token will be backed by assets duly blocked. (For now it only receives support from its community, there are not many exchanges that allow it to be used so it has a disadvantage with other stablecoins.)