Maven settings.xml supports a lot of configurables (see https://maven.apache.org/settings.html) However, the settings.xml parser in JBoss Modules' class MavenSettings is quite limited.

WildFly Swarm relies on JBoss Modules' support for Maven artifact resolution quite heavily, and as I was testing Swarm on OpenShift this week, I found two significant gaps:

1. Support for mirrors is completely missing. (This is AFAIK commonly used when there's a corporate Maven proxy. It is also prominently advertised in OpenShift Java images. It seems quite common to deploy a Maven proxy in an OpenShift cluster and use the Java images' MAVEN_MIRROR_URL environment variable, which sets up a mirror of external:* in the settings.xml, to significantly speed up OpenShift Java builds.)
2. Support for conditional activation of profiles is missing. (E.g. the Red Hat OpenShift OpenJDK S2I image activates the Red Hat Maven repo based on presence of a system property.)

There are probably more things missing, but I ran into these two.