Currently frxEth/ETH and sfrxEth/ETH are supported.
Frax Dual Oracle Price Logic
The frxEth price is determined from two onchain price sources. The first price source is the frxEth / ETH Curve pool EMA Oracle - 0xa1f8a6807c402e4a15ef4eba36528a3fed24e577. This price is bounded to be 0.7 at the lowest (0.7 frxEth = 1 ETH) and 1 at the highest (1 frxEth = 1 ETH).
This price from Uniswap is similarly bounded between 0.7 and 1, mirroring the Curve price.
The lower of these prices is returned as priceLow and the higher is returned as priceHigh. These prices are then written to the frxEth / ETH Frax Oracle.
Simply retrieves the pricePerShare() from the sfrxEth contract, retrieves the priceHigh and priceLow in the same manner as the frxEth Dual Oracle outlined above, and returns the following equation: