A linux OS uses the tzdata package, which has your iana link as source.
But in OpenEmbedded, this package is split into different sub-packages for space reasons, zo you have tzdata-europe, tzdata-asia, etc. Appearently that was still too big and/or not handy for the boxes in the beginning of the OpenPLi era, since there is a custom recipe that splits of a few entries for each timezone, and then maps other timezone names to it. So you have all the Western European, and African cities pointing to the "CET" timezone definition, which is not correct in all cases..
So the UI should give the user to select the correct timezone, as supported by tzdata.