Well, geolocation
For anyone interested, you can find a list of stuff the proposed tracking would actually track here:
https://metrics.etherpad.mozilla.org/ep/pad/view/ro.9e6LG/latest?
it's mostly fairly dull stuff, although I suspect the data on your system hardware and Firefox settings would be enough to identify someone fairly strongly, given the research that's been done on browser ID strings.
As far as location goes, it specifies "Geo Location - country + region, from server end. -to be done on the server" - note 'country and region', so this is your typical 'derive an approximate location from IP address' geolocation thing (commonly done by web server admins on their server logs too), it's not going to use your precise position, by the looks of things. That would be a lot more worrying indeed.