In general, we try to ensure that we log things that directly affect (a) what a member sees/can do or (b) how the system processes something.  So for example, a config that alters rates or dividend servicing settings, or that changes a member’s permissions or their personal info, that sort of thing, would definitely be written to a log. 
 
However, while many of our configurations do log to file maintenance, there are some configs that are simply informational-only codes, with free-form text, intended to be used for informational purposes only or for marketing uses.  They don’t cause any functionality to happen, they aren’t required by any process, members never see them.  In other words, the system doesn't really use them for anything, and the CU uses them as information only.  An example would be the configuration for new membership/account reason codes.  Changes to these types of configurations may not be logged to the file maintenance table.  (We do typically log when you add or remove one of these types of codes from a member's account, though.)

If you are curious whether an employee accessed a particular configuration, this information is recorded in the SECAUD table.  This table simply shows whenever an employee accesses any tool in CU*BASE.  It doesn't show what they did while in there, but does give you a clue as to who may have inadvertently accessed the configuration.  

There is a canned Query over this table:  Tool #162 Audit Insider/Employee Activity (SECAUD).