Confusion surrounding metadata/tombstone purge interval

A few topics coming together here:

• The 5.1 docs refer to "metadata purge interval" (https://docs.couchbase.com/server/5.1/settings/configure-compact-settings.html#establishing-auto-compaction-settings) whereas the 5.5+ docs call it "tombstone purge interval", (https://docs.couchbase.com/server/5.5/settings/configure-compact-settings.html#tombstone-purge-interval) yet in the 6.5.1 UI it is still "metadata",
• The CLI just calls it "metadata purge interval" for setting-compaction (https://docs.couchbase.com/server/6.0/cli/cbcli/couchbase-cli-setting-compaction.html#options) but just "purge interval" when creating a bucket: https://docs.couchbase.com/server/current/cli/cbcli/couchbase-cli-bucket-create.html
• Within the product itself:
  • When creating a bucket in the UI, the "metadata purge interval" is hidden under 'advanced settings' for Couchbase buckets but not for Ephemeral which led to some confusion about whether it could  even be set at the bucket level for Couchbase buckets (because it was hidden)
  • In the cluster-level auto-compaction UI, the "metadata purge interval" explicitly says it only applies to Couchbase buckets, but the same name is given to the setting at the bucket level for Ephemeral buckets
  • When changing cluster-level setting, it is only inherited by Couchbase buckets and not Ephemeral buckets even though it is the same name.

All of the above creates a pretty confusing experience for the user trying to manage their clusters and buckets.

Vaidas Gasiunas for FYI from our conversation earlier.