External plugins unavailable, 4.18 & 4.19
After upgrading to 4.18 and now 4.19 due to this, no external plugins are available in Items > Add New Items. Ostensibly these may need to be installed separately (see last line) but there's no info on how to do that (if indeed I need to do so, vs this being a bug). They're definitely not included as folders in the build, and there doesn't appear to be a separate xfce4-panel-plugins.
Any guidance appreciated. Per the other thread, my panel is now missing various background-running application icons e.g. audio control, bluetooth, Dropbox, NAS version of dropbox, redshift icon, psensors & memory sensor, network manager, possibly others.
Thanks!