/**
     * Get the value for the key 'app.extension.names'. <br>
     * The value is, e.g.  <br>
     * comment: Extension names for application customization.
     * @return The value of found property. (NotNull: if not found, exception but basically no way)
     */
    String getAppExtensionNames();

    /**
     * Get the value for the key 'app.extension.names' as {@link Integer}. <br>
     * The value is, e.g.  <br>

- ACTION REQUIRED : In CoreDNS v1.7.0, [metrics names have been changed](https://github.com/coredns/coredns/blob/master/notes/coredns-1.7.0.md#metric-changes) which will be backward incompatible with existing reporting formulas that use the old metrics' names. Adjust your formulas to the new names before upgrading. 
  
  Kubeadm now includes CoreDNS version v1.7.0. Some of the major changes include:

breakpoint-next(sm, (xs: 0, sm: 576px, md: 768px, lg: 992px, xl: 1200px))\n//    md\n//    >> breakpoint-next(sm, $breakpoint-names: (xs sm md lg xl))\n//    md\n@function breakpoint-next($name, $breakpoints: $grid-breakpoints, $breakpoint-names: map-keys($breakpoints)) {\n  $n: index($breakpoint-names, $name);\n  @return if($n != null and $n < length($breakpoint-names), nth($breakpoint-names, $n + 1), null);\n}\n\n// Minimum breakpoint width. Null for the smallest (first) breakpoint.\n//\n//    >> breakpoint-min(sm,...

xl: 1200px, xxl: 1400px))\n//    md\n//    >> breakpoint-next(sm, $breakpoint-names: (xs sm md lg xl xxl))\n//    md\n@function breakpoint-next($name, $breakpoints: $grid-breakpoints, $breakpoint-names: map-keys($breakpoints)) {\n  $n: index($breakpoint-names, $name);\n  @if not $n {\n    @error \"breakpoint `#{$name}` not found in `#{$breakpoints}`\";\n  }\n  @return if($n < length($breakpoint-names), nth($breakpoint-names, $n + 1), null);\n}\n\n// Minimum breakpoint width. Null for the smallest (first)...