also, because this is being served from the CDN, you'll want to cachebust `settings.PREINSTALL_TEST_PLAN_URL`.

I would consider doing this:

```python
PREINSTALL_TEST_PLAN_URL = 'docs/app-test-template/app_test_template-en.v1.xlsx'
```

then in the HTML

```html
<a href="{{ media(settings.PREINSTALL_TEST_PLAN_URL) }}" download>...</a>
```