This artifact originates from the Orbit Project at Eclipse, it is an osgi bundle and is signed as well.
'org.eclipse.jetty.orbit:javax.mail.glassfish:1.4.1.v201005082020'
<dependency>
<groupId>org.eclipse.jetty.orbit</groupId>
<artifactId>javax.mail.glassfish</artifactId>
<version>1.4.1.v201005082020</version>
</dependency>
<dependency org="org.eclipse.jetty.orbit" name="javax.mail.glassfish" rev="1.4.1.v201005082020"/>
"org.eclipse.jetty.orbit", "javax.mail.glassfish", "1.4.1.v201005082020"