I think it will be nice to have such a special page sub-set. Wikis reusing content from other wikis (e.g. Wikimedia or other projects) utilizing this extension would benefit for knowing if a module is missing, etc. post importation/creation to get the show running.
Currently we have a long standing, simple-to-follow & logic based maintenance group of generated listings. This group has a sub-set of complimentary Special: pages within it detailing specific maintenance deficiencies per a set group of namespaces. This sub-set is illustrated in the table below...
| Uncategorized categories | Unused categories | Wanted categories |
| Uncategorized files | Unused files | Wanted files |
| Uncategorized pages | Unused pages | Wanted pages |
| Uncategorized templates | Unused templates | Wanted templates |
.
In short, this proposal requests building upon the existing "foundation" of maintenance Special: pages illustrated in the above table by adding the following equivalent for the Module namespace to it ...
| Uncategorized modules | Unused modules | Wanted modules |
.
The caveat in adding such a sub-set would seem to result in a rather "large" maintenance group section in the end.
If so, further discussion of any possibility in filtering each specific maintenance task by namespace(s) to shorten the list is needed (iow- not sure filtering of such Special: cached pages is even possible never mind feasible).