Hey,
Felix was referring to this discussion about using $INDEX as a risk backstop in the case of a token within an index product like DPI going to 0. Index stakers will take the hit and tokens will be auctioned off to cover the loss.
This is similar to the AAVE safety module where AAVE stakers are rewarded for staking their tokens, knowing that in a shortfall they will be sold off up to 30% and auctioned to the market. mStable also has a token that serves as a backstop for their meta tokens.