M2E plugin execution not covered
To solve some long-standing issues, m2e 0.13 requires explicit instructions what to do with all Maven plugins bound to "interesting" phases (see M2E interesting lifecycle phases) of project build lifecycle. We call these instructions "project build lifecycle mapping" or simply "lifecycle mapping" because they define how m2e maps information from project pom.xml file to Eclipse workspace project configuration and behaviour during Eclipse workspace build.
Project build lifecycle mapping configuration can be specified in project pom.xml, contributed by Eclipse plugins and there is also default configuration for some commonly used Maven plugins shipped with m2e. We call these "lifecycle mapping metadata sources". m2e will create error marker like below for all plugin executions that do not have lifecycle mapping in any of the mapping metadata sources.
Plugin execution not covered by lifecycle configuration: org.apache.maven.plugins:maven-antrun-plugin:1.3:run (execution: generate-sources-input, phase: generate-sources)