Checked Google Play and the album does cost money, with an option to buy individual songs. No idea if you can store them afterwards or in what format they come in though. You can listen to the songs for free on Spotify, but that's it, you can only listen.
Honestly I'm fine with it, since CDPR has no obligation to offer the extended version for free as a download, it would be nice if they would, but I don't feel entitled to it. The OST I got for free via physical copy/GOG is already pretty extensive and I'm grateful for that.
Thank you for looking into it for us, it's a bit clearer now.
I don't feel entitled to the entire extended OST, however it would be fair to include tracks we can hear ingame, to the gog OST, like for example, instrumental of Oxenfurt track and Wolven storm song.
I could be mistaken, but wasn't the official statement in regards to the incomplete ost that it would spoil ingame content too soon?