IQ Backup Options - am I understanding correctly?
From https://infoqubeim.com/drupal5/node/987:
# 2.2.1 - Backups created on program close (# 2.2.1) use rotating numbers .SNBK0, .SNBK1 and .SNBK2 e.g TestFile.SNBK1 (where .SNBK0 is the current backup, .SNDB1 is 1 day old and .SNDB2 is 2 days old). This is NOT enabled by default.