@SoapDog

The sbot/ssb-server command is plugins.install. It is available currently only in ssb-server CLI or Scuttle Shell. (Other ssb-server distributions don't include the plugin feature.) There also a bug where ssb-plugins's install command requires a non-null value in the second argument. Adding a dummy flag when using sbot/ssb-server makes it add an object in the second argument which works:

sbot plugins.install ssb-blobs-purge --make-it-work

or with sbotc:

sbotc plugins.install '"ssb-blobs-purge"' {}

This installs the plugin from npm: https://www.npmjs.com/package/ssb-blobs-purge