GNU/Linux KDE Neon Installing Broadcom BCM43142 Driver Guide
The linked tutorial shows you step-by-step How to Install Broadcom BCM43142 Wi-fi/Bluetooth Driver on KDE Neon LTS GNU/Linux desktop – Step by step Tutorial.
The Package Provides the Source Code for the wl Kernel Modules and makes use of the DKMS Build Utility to Install them for the Running Kernel.

GNU/Linux KDE Neon Broadcom BCM43142 Driver Installation Guide