Sabaki Software

Sabaki describes itself as An elegant Go board and SGF editor for a more civilized age.

It is an Electron application. It is fully SGF4 compliant. It allows a limited use of Markdown in your reviews. It also supports GTP which means it can be used as a GoClient. The source code is visible on GitHub

To install, download the release relevant to your platform. You may need to install a GTP (Go Text Protocol) Engine to play against an AI.