1) Assigned regular expression ".*" to standard view filter "Use a regular expression to include jobs into the view", which caused all jobs to be listed in the view.
2) Added "Regular Expression Job Filter" of Match Value "Email recipients" with a Regular Expression of ".com."
3) Set Match Type to "Exclude Unmatched - Filter out jobs that don't match this filter".
Result: No jobs appear in the view. I expected all jobs to be listed (every job has one or more .com. values for email recipients).
4) Set Regular Expression to ".*", and this also resulted in no jobs listed in the view.

No errors have appeared in the Jenkins server.log.

Looking at a sample job config.xml file, here's the location of the email addresses I'm expecting the filter to match (<recipients>...</recipients>):

<reporters>
<hudson.maven.reporters.MavenMailer>
<recipients>[address1@redacted].com [address2@redacted].com</recipients>
<dontNotifyEveryUnstableBuild>false</dontNotifyEveryUnstableBuild>
<sendToIndividuals>false</sendToIndividuals>
<perModuleEmail>true</perModuleEmail>
</hudson.maven.reporters.MavenMailer>
</reporters>

This plugin is only useful to our environment if we can match on email recipients (and it will be extremely valuable it it can!), thus the "Major" priority.