Be lucky if you own any of these handsets - Optimus L70, G2 Mini, G3 Beat and LG G3 S. As a Christmas gift, CyanogenMod is offering nightly builds which can be accessed at once for flashing and download. It is great news indeed as mid-level and older handsets will not receive upgrades for Android 6.0 Marshmallow. It is a privilege that you'll surely enjoy with the features that CyanogenMod 13 will provide on the latest Android updates.
If you don't know what Android is or if you're just new to the Android world, CyanogenMod or simply CM is an open-sourced operating system that is based on the Android platform. Each time Google has an official release, third-party and original codes are added to make an intensified version of the release. In this case, Android 6.0 Marshmallow is the basis for CyanogenMod 13. And as several devices need official upgrades, it simply means those who upgrade to CM 13 will enjoy unique features, even though it remains unofficial.
Optimus L70 is an entry level device, while the LG G2 Mini is an older variant of the G2 flagship. The LG G3 Beat is a variant of the G3 flagship and offered in other territories. The LG G3 S is a lower version of the G3 flagship, which was released late of 2014.These are handsets that work with other Android mobile phones and tablets from various OEMs.
But certainly there are lots of unofficial systems and builds, you will just have to install at your own risk. Your handset needs to be rooted and due to the rooting, the warranty becomes void. If you need to access Google Play Store and other Google services, you need to ensure you have the latest GApps ZIP package.