The way I've dealt with this before is reference the ticket number in the commit message. Now the only tickets you ever need to review are the ones relevant to the element in question, and only those creating or modifying that particular property, which should be evident in your commit log.
You don't specify a language but I'd assume that is the footer definition/html and any scripts or styles invoked by it.
But once you have an answer, it would be wise to document it in confluence somewhere, even if it's something like "Footer green per request from Director, Mr. Smith" or "Footer color: arbitrary, green to differentiate profile pages. Verify changes with Director."
How to organize the documentation so that it isn't difficult to navigate is another difficult question that is more art than science - one which has never been satisfactorily solved anywhere I've worked once complexity reaches a certain point, but I leave that exercise to the reader.