The Jakarta Mail API is a set of abstract APIs that model a mail system. (Jakarta Mail was previously known as JavaMail.)

https://eclipse-ee4j.github.io/mail/FAQ#1

Until Magnolia 6.2.17 Jakarta Mail would be pulled in transitively via

[INFO] |  +- info.magnolia.rest:magnolia-rest-services:jar:2.2.11:compile
[INFO] |  |  +- io.swagger.core.v3:swagger-annotations:jar:2.1.12:compile
[INFO] |  |  \- org.jboss.resteasy:resteasy-multipart-provider:jar:4.6.1.Final:compile
[INFO] |  |     +- com.sun.mail:jakarta.mail:jar:1.6.5:compile 

This is no longer the case as of 6.2.18. Whilst still functional, the mail module could likely use the latest mail API artifact.