KiCad is an open-source electronics CAD tool. You can create schematics and design PCBs using an extensive open source library of parts. View your resulting PCBs in 3D and export to gerbers for manufacturing.
This is also the first stable point release made since switching to gitlab for main kicad source code hosting.
A list of all of the fixed bugs since the 5.1.5 release can be found on the KiCad 5.1.6 milestone page https://gitlab.com/groups/kicad/code/-/milestones/1. This release contains several critical bug fixes so please consider upgrading as soon as possible.
Version 5.1.6 is made from the 5.1 branch https://gitlab.com/kicad/code/kicad/-/commits/5.1/ with some cherry picked changes from the development branch.