found this in my old notes,
<?xml version="1.0" encoding="UTF-8"?>
<FileTypeList version="2.0">
<FileType id="50001" group="Other files" description="bitcoin wallets" features="" extension="dat">
<Begin combine="OR">
<Signature>\x61\x15\x06\x00</Signature>
<Signature>\x00\x06\x15\x61</Signature>
<Signature>\x62\x31\x05\x00</Signature>
<Signature>\x00\x05\x31\x62</Signature>
<Signature offset="12">\x61\x15\x06\x00</Signature>
<Signature offset="12">\x00\x06\x15\x61</Signature>
<Signature offset="12">\x62\x31\x05\x00</Signature>
<Signature offset="12">\x00\x05\x31\x62</Signature>
<Signature offset="12">\x53\x22\x04\x00</Signature>
<Signature offset="12">\x00\x04\x22\x53</Signature>
<Signature offset="12">\x88\x09\x04\x00</Signature>
<Signature offset="12">\x00\x04\x09\x88</Signature>
</Begin>
<End combine="OR"/>
</FileType>
</FileTypeList>
i think it's supposed to be used in
https://www.google.com/search?q=R-Studio I can't vouch for it, but like i said before if you recover using photorec anything that resembles a wallet database (bdb) it will have a .db extension and be missing the first 8kb or less, that will probably be seperared, the wallet wont read correctly but you can fix it