#include config of backendlayout

-- BackendLayouts/
   |-- default.ts
   |-- default1.ts
   |-- default2.ts
   |-- default3.ts
   |-- default4.ts
   |-- default5.ts
   |-- ...

### include all folder tses extensions="ts"
<INCLUDE_TYPOSCRIPT: source="DIR:EXT:custom_template/Configuration/TypoScript/PageTSconfig/BackendLayouts" extensions="ts">

### old way to include default.ts
<INCLUDE_TYPOSCRIPT: source="FILE:EXT:custom_template/Configuration/TypoScript/PageTSconfig/BackendLayouts/default.ts">
<INCLUDE_TYPOSCRIPT: source="FILE:EXT:custom_template/Configuration/TypoScript/PageTSconfig/BackendLayouts/default1.ts">
  ...
<INCLUDE_TYPOSCRIPT: source="FILE:EXT:custom_template/Configuration/TypoScript/PageTSconfig/BackendLayouts/defaultn.ts">