Thanks!

About the HBD debt limit and the haircut.

When the debt is higher then the limit (10%, now, 20% to 30% in the future), the blockchain will no longer give a 1$ rate for a HBD to HIVE conversions.

The rate that the blockchain will apply for HBD depends on the debt level.
For example for a limit of 10% debt, if the debt level is 11%, the blockchain will give around 0.91$ HBD to HIVE, and if the debt is 20%, (double then the 10% limit) then the blockchain will value HBD to HIVE conversions for 0.5$, basically giving a 0.5$ price for HBD.