I just downloaded VLC 3.0 Beta (using ubuntu ppa) and I wanted to know how to set it up to stream to chromecast. It's in the repo's NEWS that the feature has been added. Numerous news outlets are covering it. But, there is no example of how to actually use it yet.
I know it's not in the GUI (having searched the source code). And, I have no idea how to use the code from the command line.
Here is the Ubuntu PPA that I used to install it. However, it shouldn't matter. Nor, should the OS or system matter. It's just software. You can build it yourself or download a binary ("nightly") here.