dev-java/junit-5.9.2 should list the Maven artifacts it installs in the MAVEN_PROVIDES variable inside the ebuild. However, the MAVEN_PROVIDES value for this ebuild requires extra attention because the ebuild has these special properties: - The ebuild conditionally installs some artifacts depending on the USE flags. For example, org.junit.vintage:junit-vintage-engine:5.9.2 is installed if and only if USE="vintage" is set. When the said USE flag is disabled, the files installed by the ebuild no longer provide org.junit.vintage:junit-vintage-engine:5.9.2. - The ebuild installs files for at least 8 Maven artifacts; even more artifacts will be installed when more USE flags are enabled. Thus, the value of MAVEN_PROVIDES will contain at least 8 artifact coordinates and thus be too long, unless multi-line MAVEN_PROVIDES values are supported (https://bugs.gentoo.org/903666).