Major Description
Before Solr 7.*, cache maxSize and autowarm settings were exposed in JMX along with cache metrics. There was a textual attribute "description" which could be parsed to extract maxSize and autowarm settings. This was very useful for various monitoring tools since maxSize and autowarm could then be displayed on monitoring charts (one could for example compare current size of some cache to its maxSize without digging through configs to find this setting).
Ideally maxSize and autowarm count/% would be exposed as two separate attributes, but having a single description field (which can be parsed) would also be better than nothing.