A package is enabled if it is scheduled to run at server startup and is deliverable by the request processor.
If a Tcl library file (*-procs.tcl) or query file (*.xql) is being watched, the request processor monitors it, reloading it into running interpreters whenever it is changed. This is useful during development (so you don't have to restart the server for your changes to take effect). To watch a file, click its package key above, click Manage file information on the next screen, and click watch next to the file's name on the following screen.