dovecot.index.log files: what are they?

[Thomas Klausner]

Hi!

I have lots of these files:

/home/wiz/Mail/my-folder-name/cur/.imap/1238738125.13533_23713.danbala:2,S/dovecot.index.log

What are they for?
Why are they here?
Can I remove them?

 Thomas