Module to manage submodules What I want to do is be able to tell what the parent of a submodule is on the admin/modules page. There is little to no indication of what it belongs to sometimes.

Example, under the Administration group, I have a module called "Actions permissions." I have no idea what this module is for, the purpose of the module, why I would want it, or what it belongs to. It's just out there. I know it's a child of something else, but there is no indication of that anywhere. I could go on the server and grep it but I think it might be helpful to people to have a way to determine the parent.

So is there a module that:

A) will group submodules in a hierarchy-type view under their parents? Or
B) a module that simply lists what the parent is on the module item itself like we do with Requires:
There's no such concept as parent and sub/child-modules in Drupal. You'd have to define what you consider to be the parent-child relationship, pick what physical properties of the module you're going to use to describe that relationship, and code a solution from there.

Drupal's own native mechanism for grouping modules is using the package key in the module .info file. In the case of Actions Permissions, for example, the package is defined as "Administration", so you can find it under the "Administration" fieldset, grouped with other modules that are considered to have (loosely) related functionality by their respective authors.

On a slightly un-related note, but you can improve the UI of the modules page using Module Filter if it's becoming unwieldy.