Hi,
Based on a quick look, it looks like someone ported the MSP430 gdbproxy to work with AVR devices. However, based on the project stats (0 issues, 0 releases, 4 commits), it is likely in the proof-of-concept stage and may not work reliably at all.
If you would like to try it out with VisualGDB, you can build it and use the “Custom GDB Stub” setting in VisualGDB debugging properties, however if you are not prepared to troubleshoot the problems of the gdbproxy itself, we would not advise doing that and we would recommend using the more popular AVaRICE tool (included in our AVR toolchain).