Issue #2498691 by cilefen, mesch, deepakaryan1988, RavindraSingh, honzakuchar, darol100, kattekrab, Cottser, David_Rothstein: "Install and set as default" link on the Appearance page doesn't work

Issue #2499615 by honzakuchar: Docblock interface Drupal\Core\Extension\ThemeHandlerInterface::uninstall typo