Plugin installation failure doesn't have any information
At present, attempting to install the ZoneMinder plugin seems to fail during the post install script, but there doesn't seem to be a way to determine what went wrong. In the GUI, the only indication is the progress dialog box displaying the text "Exception: RuntimeError: occured, destroyed zoneminder."
Thankfully it does indeed destroy the partial jail so conflicts don't occur with duplicate names (since you can't choose the name of the jail when creating a plugin for some reason), but it would be nice to know if there's something else that can be done, some syslog entry or whatever that tells me any information at all.
Failure message now reads:
zoneminder's post_install.sh had a failure Exception: RuntimeError Message: Last 10 lines: jexec: execvp: /root/post_install.sh: Permission denied Partial plugin destroyed
I think the output isn't being properly html-ified, but unfortunately the post_install.sh script was apparently not intended to have its output scrutinized, so not sure where permission is being denied...