What kind of bullet characters and how many hierarchies for bullet lists are supported?

In the package descriptions displayed in the Ubuntu Software-Center, I'd like to know what characters (beside »-« and »*«) are currently supported there to create bullet lists? And how many hierarchies for bullet lists are supported? How do I have to format the text to get an indented bullet list with a sub-hierarchy?

I stumbled upon this while translating the package description of »pidgin-otr«, where you can only see a single-hierarchy bullet list though the author obviously intended to have sub-hierarchies for the bullet list.

Thank You very much in advance for getting this information out (or pointing me to the right place to look for answers on this – beside of auditing the source code).

Regards,

Dennis