Trying to figure out the same.  Here is what i found quickly:

Peers.dat is used to store the peer to peer connections needed to pass the blockchain information, of what transactions have occured, around the Feathercoin network.

Peers.dat used to be plain text, so you could see who was attached, but is now is not human readable directly. You can still see the peers that are attached by starting the debug console in Feathercoin help, and typing getpeerinfo. It shows the IP addresses and version number of clients attached to your wallet.   Maybe the same for CraigsCoin

found this too on the https://en.bitcoin.it/wiki/Data_directory#Directory_Contents


    .lock
        BDB lock file

    bitcoin.conf [optional]
        Contains configuration options.

    blkxxxx.dat [Versions prior to v0.8.0]
        Contains concatenated raw blocks. Stored are actual Bitcoin blocks, in network format, dumped to disk raw.

    blkindex.dat [Versions prior to v0.8.0]
        Indexing information used with blkxxxx.dat

    __db.xxx
        Used by BDB

    db.log
    debug.log
        Bitcoin's verbose log file. Automatically trimmed from time to time.

    wallet.dat
        Storage for keys, transactions, metadata, and options. Please be sure to make backups of this file. It contains the keys necessary for spending your bitcoins.

    addr.dat [Versions prior to v0.7.0]
        Storage for ip addresses to make a reconnect easier

    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].

The data, index and log files are used by Oracle Berkeley DB, the embedded key/value data store that Bitcoin uses.

So my understanding is that peers.dat is modified each time the wallet is launched.