jm b®æ>Z´^mHÊÙÙÓ¶Ý&°»éL´I don't think you need it for bchwallet. It's only used by the searchrawtransactions RPC AFAIK which lets you query any address (as opposed to solely the addresses in your wallet).
https://whatsonchain.com/tx/e3c47adcdf10f641cdf5790c055a7e9cd91497bb10b465035324eed5be2179ed