Proposal

As I have many Prometheus instances with different retention settings defined different repositories, I'd love to have a dashboard where to combine them all with a Prometheus query.

I can find the metrics prometheus_tsdb_retention_limit_bytes for --storage.tsdb.retention.size (clear enough) as well as prometheus_tsdb_size_retentions_total and prometheus_tsdb_time_retentions_total (no idea what these are) but I don't find a metric reflecting the --storage.tsdb.retention.time setting (I've not tried --storage.tsdb.retention as I don't use it and I understand it's deprecated since a while ago).

So, would it be possible to add a metric like prometheus_tsdb_retention_time_limit_days or something, with an appropriate conversion from --storage.tsdb.retention.time units?