Resolves #12623 [Hackday] [2.7] Add a deprecation note about Debug compo...

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | yes
| Tests pass?   | yes
| Fixed tickets | #12623
| License       | MIT
| Doc PR        | 
Is a custom constructor necessary? Adding this just below the `namespace` should work too, right?