Package &1 has no software component assignment for transport

What causes this issue?

Package &v1& is valid for programm-based SWC transport only if it is
assigned to a modifiable system software component (see Properties ->
Transport Attributes).

System Response

The assignment of the specified package &v1& is denied.

How to fix this error?

Choose a package that is assigned to a system software component that is
defined as modifiable (transaction SE03 -> Set System Change Option ->
Software Component).

Procedure for System Administrators

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

Error message extract from SAP system. Copyright SAP SE.