https://en.bitcoin.it/wiki/Data_directory
peers.dat [Versions v0.7.0 and later]
Storage for peer information to make a reconnect easier. This file uses a bitcoin-specific file format, unrelated to any database system[1].
fee_estimates.dat [Versions v0.10.0 and later]
Statistics used to estimate fees and priorities. Saved just before program shutdown, and read in at startup.
peers.dat [Versions v0.7.0 and later]
Storage for peer information to make a reconnect easier. This file uses a bitcoin-specific file format, unrelated to any database system[1].
fee_estimates.dat [Versions v0.10.0 and later]
Statistics used to estimate fees and priorities. Saved just before program shutdown, and read in at startup.
Basically it's useless and there is nothing to do with them really and it's for Bitcoin Core ? still can't figure why they are on my D disk though . anyway thanks Amph appreciate it
