From post 19/437 in the LG V10 review thread, there are proofs. With screenshots. From owners. Many other credible members said so too in that thread and others. I believed them.
I'd be glad to be wrong. I'm searching for good audio like you all are.
http://www.head-fi.org/t/785335/lg-v10-hi-fi-audio-quality-review-on-serious-audio-performance/15
Please inform us if this is false... and why.
You can start by reading the other two V10 threads, which have been pretty detailed and instructive as to what apps/players are working and which are not. In particular, this thread:
http://www.head-fi.org/t/782706/lg-v10-new-ess-chipped-flagship-android-phone-from-lg
At the very least, on my phone I know the LG app works, Double Twist player, Google play (streaming), Tidal (streaming), and BubbleUpnP (using Tidal or Doubletwist).
Others have found that Neutron works, though you have to "trick" it into working. I'm not bothering with it. I also think Shuttle works, and maybe a few other streamers.
Many of us have been careful to clarify the exactly how we know the DAC is actually working, beyond simply seeing the HiFi notification, which does not mean that the HiFi DAC is actually being used. The first way is to go into the HiFi settings and look for the Left and Right balance adjusters, but then, importantly, you'll hear an obvious gain/volume difference when you toggle the HiFi switch on and off. This is exactly the case with the LG stock player, Google Play, Tidal, and DoubleTwist (in my experience). Others have noted other players that are confirmed as well.
Moreover, there is now discussion as to whether or not using certain types of adapters trigger the HiFi DAC or not, regardless of the player. I cannot confirm, as I haven't been exploring this, nor really paying attention.
Bottom line, the DAC works, it's easy to get it to work, it's easy to find players and streaming apps that work with it, and beyond that, you get enormous local storage, swappable batteries, and arguably the best camera on a smart phone you can get.