CyanogenMod 13, based on Android 6.0 Marshmallow, first arrived in November 2015. It was soon switched to Android 6.0.1, and continued to be the main branch of CyanogenMod until version 14.1 was released one year later. After the CyanogenMod community re-organized into LineageOS, the distribution was renamed to LineageOS 13.
At this point, most of the devices that had LineageOS 13 have either been updated to v14.1, or dropped entirely (usually due to inactive maintainers).
LineageOS 13, based on Android Marshmallow, is now discontinued was written by the awesome team at Android Police.