Where is it used? Does LG use it in their TV's or are they using the closed source edition?

LuneOS seems to be using some of the code from webOS Open Source Edition:

https://webos-ports.org/wiki/LuneOS-webOS-OSE_Migration_Stat...

It's too bad that LuneOS hasn't had a release since 2019.

I don't think the UI for the LG webOS TVs is open source: https://www.engadget.com/2018-03-19-lg-webos-open-source-edi...