what is a 'not compatible' plug-in?

[cat6man]

why do some plug-ins show up but say 'not compatible'?
these also have no way to be installed.....which i guess makes
sense............does this mean someone is working on porting
to sage7 but has not completed the task?

[Opus4]

If you look at the details screen for the plugin, it should show why it is not considered compatible.

- Andy