Check out this very useful resource: http://opengl.delphigl.de/
It’s a huge database of which cards support which extensions across all vendors. You can check for a specific extension and see which products support it, and you can click on specific products and see what extensions they support. It’s data gathered from real end-user machines, so it takes into consideration the lag with which users pick up new drivers
The answer in this case is...
No. It is unsupported on Radeon 5xxx or 6xxx cards. There is no chance it will be supported because it requires GCN hardware.