What's this 15-20 min GS "career aspiration" phone interview about?

i applied for GS Hong Kong SA position. Got an email from HR and she said the process goes like this:

first, a 15-20 minute firm wide phone interview if i pass, a regular first round interview, phone or in-person if i pass, super day.

two days later i got an email from my interviewer and apparently the purpose of the 15-20 min. interview is to "gather additional details of my interests and career aspirations".

Anyone familiar with this stuff? What kind of questions should I expect/how should i prepare?

Thanks a lot.