Loving the addon so far ! Been using it for months now and had zero bugs, it has simply just worked 100% of the time, which is amazing.

I have a feature request though which in my opinion would add to it's value immensely.

As the core goal of this is not necessarily reducing the number of loaded tabs, but rather reducing CPU (and by extension, battery/heat/power) usage, RAM and disk I/O. So what would be great, would be the possibility to unload tabs by their resource usage. This data is available in firefox profiler capabilities but it's rather cumbersome going checking the data by hand through the debugging tools.

The feature could be added as a new condition to be mixed with others, like after X open tabs unload tabs which use >X% CPU and/or >X MB RAM / unload the next highest resource usage tab / after X minutes close tabs using X% cpu or X MB RAM / only close tabs which use >X resources.

Adding a tooltip when hovering over a tab which displays their CPU/RAM usage would be neat too.

For my use case as I've moved the FF profile to ram disk and I have plenty of RAM, I don't really care about disk I/O or RAM usage, but badly coded CPU-heavy scripts on some sites makes browsing a slog (not to mention killing the battery when on a laptop), hence this plugin. But a static site which runs very little to no scripts does not really contribute to the resource usage, unlike some badly behaving sites.

And systems which are more starved of RAM, could start unloading tabs by highest RAM usage instead, when total RAM usage exceeds X MB as a condition, for example.

Anyway, just my two cents for now, and keep up the good work !