The exact file is likely http://xtrapath1.izatcloud.net/xtra.bin, which contains the gps almanac. Turns out that aGPS implementations differ per vendor, which is why the domain is qualcomm owned.
Required? Only if you want fast GPS fixes / aGPS.
Edit: File may also be http://xtrapath1.izatcloud.net/xtra2.bin or similar; My point was that the connection is likely to do with downloading data to speed up GPS. Different files exist for different combinations of nav networks, e.g. xtra2.bin is GPS+Glonass. The file format is proprietary. More background in this security advisory.