we are in the process to review all the variables currently recorded in analytics as our implementation has been done in 2015 (well before any of the current analyst was in the team) and not been documented at all (I guess it happens a lot). For the moment we want just to have a list of all the variables (evar, prop, event) and write down the logic that populates them so all the users know what they are using when they are building a report.
I have checked with Adobe and we haven't got any VISTA rules on our account so I guess the only way we can populated the variables are through:
data collection (we use tealium as tag management)
The issue I have got (and I'd like to have your view about this as I'm not a developer) is that in analytics I can see some evars and props that are populated but they are not defined in either tealium or processing rules menu. I have checked on the page code as well and I'm pretty sure they are not there either (again I'm not a web developer)