texlive-core-2008 has this dependency: ">=media-libs/libpng-1.2.43-r2:0". It can cause problems if user want to install libpng-1.2.43-r3:1.2. Reproducible: Always Steps to Reproduce: 1.emerge texlive-core 2.unmask libpng:1.2 (but not libpng-1.4) 3.emerge -uDN texlive-core Actual Results: Block between media-libs/libpng-1.2.43-r2:0 pulled by texlive-core and libpng-1.2.43-r3:1.2 installed by user. Expected Results: Normal working with choosed libpng
slot :1.2 only installs libpng12.so.0 for binary-only packages. therefore the depend on slot :0 is correct.