On May 1, 2018, a Swedish Air Force S102B Korpen has started operating in the eastern Med. ...
They are equipped with sensors operated by ELINT personnel from the FRA (the Radio Establishment of the Defence), capable to eavesdrop, collect and analyse enemy electronic emissions.
Apparently Russia feels the benefit of using weapons in Syria is worth the price of potential foes learning how Russia uses them.
Of course, one can't exclude the possibility that Russia is holding back their best stuff and hoping the Swedes (and others, including America) are learning worthless information from watching Russia in Syria.
[In a pre-publication addition, this long excellent Strategypage post has a good short section on Russian electronic warfare in Syria.]