[ERROR] Failed to execute goal on project xwiki-platform-distribution-jetty-hsqldb: Could not resolve dependencies for project org.xwiki.platform:xwiki-platform-distribution-jetty-hsqldb:pom:16.4.0-SNAPSHOT: The following artifacts could not be resolved: org.xwiki.platform:xwiki-platform-distribution-war:war:16.4.0-SNAPSHOT (absent): org.xwiki.platform:xwiki-platform-distribution-war:war:16.4.0-SNAPSHOT was not found in https://nexus.xwiki.org/nexus/content/groups/public-snapshots during a previous attempt. This failure was cached in the local repository and resolution is not reattempted until the update interval of xwiki-snapshots has elapsed or updates are forced
Just means that the artifact has not yet been published by the CI. You can rebuild it locally.
This is the old snapshots repository. Please see https://www.xwiki.org/xwiki/bin/view/Blog/New%20Maven%20SNAPSHOT%20repository