I have never used jaxx wallet in iphone but AFAIK the wallet data isn't stored in the icloud backup. Since jaxx wallets allows user to have complete control over the keys, storing on a cloud backup server might expose the keys at some point of time. Hence the backup file (not completely sure) would be stored in a encrypted format in the form of .plist file which is quite useless and they would be available in the com.kryptokit.kryptokit app domain folder. I have heard people trying to break the .plist file using a sqlite but didn't come up with favorable outputs.
I just installed Jaxx on my PC (Windows) to try and locate the wallet file, and I believe this is it:
C:\Users\OmegaStarScream\AppData\Roaming\com.liberty.jaxx\IndexedDB\file__0.indexeddb.leveldb\000003.txt
I managed to find addresses, xPubs and everything else that is displayed on the UI basically, except for the private keys (they might be encrypted as I couldn't find them on plaintext). As a test, I disabled my internet connection, and then deleted the file above...
After launching Jaxx for a second time, I got asked to either create a new wallet or restore one (which should also prove that the file above is the wallet).
So, after I created a new wallet, I went to the settings to try and export the private keys... but I only got
these wallets to export PKs from. I went back to the first page to try and create a BTC or LTC wallet (since it wasn't created on launch)... but that didn't work. I was just stuck on
this window. But whenever I enabled my internet back, it worked fine!
So, unless I'm missing something, It appears to me that wallets are
not created offline except for Dash, Zcash and Dogecoin.