```html
<!-- Default back button -->
<ion-header>
  <ion-toolbar>
    <ion-buttons slot="start">
      <ion-back-button></ion-back-button>
    </ion-buttons>
  </ion-toolbar>
</ion-header>

<!-- Back button with a default href -->
<ion-header>
  <ion-toolbar>
    <ion-buttons slot="start">
      <ion-back-button defaultHref="home"></ion-back-button>
    </ion-buttons>
  </ion-toolbar>
</ion-header>

<!-- Back button with custom text and icon -->
<ion-header>
  <ion-toolbar>
    <ion-buttons slot="start">
      <ion-back-button
          [text]="buttonText"
          [icon]="buttonIcon">
      </ion-back-button>
    </ion-buttons>
  </ion-toolbar>
</ion-header>

<!-- Back button with no text and custom icon -->
<ion-header>
  <ion-toolbar>
    <ion-buttons slot="start">
      <ion-back-button text="" icon="add"></ion-back-button>
    </ion-buttons>
  </ion-toolbar>
</ion-header>

<!-- Danger back button next to a menu button -->
<ion-header>
  <ion-toolbar>
    <ion-buttons slot="start">
      <ion-menu-button></ion-menu-button>
      <ion-back-button color="danger"></ion-back-button>
    </ion-buttons>
  </ion-toolbar>
</ion-header>
```