Yes they haven't provided API document I don't know why, maybe it's in progress. With only 2 exchanges on Coinmarketcap BFG volume doesn't move at all, is in the range of $50k-70k per 24 hours if it's like this BFG won't get any rank in CMC even though ranking in CMC is important, some people use rankings as a benchmark for the development of crypto projects.
I'm following them on Coinmarketcap but with Biswap not on their cache I don't think volume will add up, Biswap is their first DEX and many of us first traded here because of its liquidity, the team should ask Biswap to get their site index on Coinmarketcap and they should also apply on Coingecko many traders are using both for comparison.