Angular 不再需要 corejs 了吗

我已经将Angular项目从版本7更新到了版本8.一切运行顺利，原理图完成了工作(可能)，我们也很好(项目甚至还在生产中).当我们更新Angular CLI时，我们总是生成一个新项目来查看真正的差异，并从中学习新的依赖项、配置等.

使用Angular CLI 8.0.4生成新的Angular项目时，新应用没有core-js作为依赖项:

"dependencies": {
    "@angular/animations": "~8.0.1",
    "@angular/common": "~8.0.1",
    "@angular/compiler": "~8.0.1",
    "@angular/core": "~8.0.1",
    "@angular/forms": "~8.0.1",
    "@angular/platform-browser": "~8.0.1",
    "@angular/platform-browser-dynamic": "~8.0.1",
    "@angular/router": "~8.0.1",
    "rxjs": "~6.4.0",
    "tslib": "^1.9.0",
    "zone.js": "~0.9.1"
  }

分析Build project core-js上的Bundle 包不存在:

"dependencies": {
    "@angular/animations": "~8.0.3",
    "@angular/cdk": "~8.0.1",
    "@angular/common": "~8.0.3",
    "@angular/compiler": "~8.0.3",
    "@angular/core": "~8.0.3",
    "@angular/forms": "~8.0.3",
    "@angular/platform-browser": "~8.0.3",
    "@angular/platform-browser-dynamic": "~8.0.3",
    "@angular/router": "~8.0.3",
    "@auth0/angular-jwt": "2.1.1",
    "@hackages/ngxerrors": "~8.0.0",
    "@ng-bootstrap/ng-bootstrap": "5.0.0-rc.1",
    "@ngx-loading-bar/core": "~4.2.0",
    "@ngx-loading-bar/http-client": "~4.2.0",
    "@nicky-lenaers/ngx-scroll-to": "~2.0.0",
    "@swimlane/ngx-charts": "~12.0.1",
    "bootstrap": "~4.3.1",
    "core-js": "~2.6.9",
    "d3-scale": "~3.0.0",
    "d3-shape": "~1.3.5",
    "date-fns": "2.0.0-beta.2",
    "ngx-perfect-scrollbar": "~8.0.0",
    "ngx-toastr": "~10.0.4",
    "rxjs": "~6.5.2",
    "tslib": "~1.10.0",
    "xlsx": "~0.14.3",
    "zone.js": "~0.9.1"
  }

为什么会有这种行为？删除core-js作为依赖项安全吗？更新的示意图是否缺少这个？在最新的项目上安装npm个依赖项时，我会收到core-js条安装后消息，但它并没有明确地出现在包描述中.