Better API documentation in skinr.api.php

I could definitely use some help with docs.

Also, for hook_skinr_theme_hooks() it says:
* @param $element
* An element.

What is an element? I would assume an object of some sort, like a block or node or something, however it is concatenated like this:
'node_' . $element

An $element in this case (and throughout skinr module) is a string. An example using blocks is: system__powered_by (the resulting theme hook is block__system__powered_by). An example node content type element: article (the resulting theme hook is node__article).
These are similar (but lack the type definition) to what's used as theme hooks to create a template file name.

A note: $module is used throughout the skinr module, but can be confusing. See #1200352: $type and $module are used interchangeably in Skinr's code; fix this.

For example, for hook_skinr_elements it says:
* @todo Needs a better description.

Is it to define the possible element ID's for a given theme function?

hook_skinr_elements() is called by skinr_preprocess(). It returns "An array of $elements based on $module and $original_hook, derived from $variables." (from inline code description). An element is what links the applied skin to a block or a node or a view, etc (see above: hook_skinr_theme_hooks()). So for element = system__powered_by and module = block and theme = bartik a specific set of applied skins can be found.

I hope that makes sense. Hopefully you can put it into better words that we can apply to the docs.

D7 reached its EOL back in January 2025, and there is no active release for D7 for this module anymore.
Development or support is not planned for D7. All D7-related issues are marked as outdated in a bunch.