When creating a deployment app in Splunk, certain files and folders are considered essential to ensure proper configuration and operation:

app.conf (in default or local): This is required as it defines the app's metadata and behaviors.

local.meta: This file is important for defining access permissions for the app and is often included.

metadata folder: The metadata folder contains files like local.meta and default.meta and is typically required for defining permissions and other metadata-related settings.

props.conf: While props.conf is essential for many Splunk apps, it is not mandatory unless you need to define specific data parsing or transformation rules.

D. props.conf is the correct answer because, although it is commonly used, it is not a mandatory part of every deployment app. An app may not need data parsing configurations, and thus, props.conf might not be present in some apps.

Splunk Documentation References:

Building Splunk Apps

Deployment Apps

This confirms that props.conf is not a required part of a deployment app, making it the correct answer.