Naming convention for parameterized getter methods (->getItem($key)).

Some classes have both regular getters, and "parameterized" getters.

$items = $list->getItems();  // All items.
$item = $list->getItem($key);   // Only the one item matching the key.

The "parameterized" getters are not really getters in the traditional sense.

I would like to propose a naming convention that makes them easier to distinguish from regular getters, and hopefully make code easier to read.
Maybe others have alternative ideas.

$items = $list->getItems();  // All items.
$item = $list->keyGetItem($key);   // Only the one item matching the key.

Use case: ExtensionList

A possible use case would be the issue about ExtensionList, #2208429: Extension System, Part III: ExtensionList, ModuleExtensionList and ProfileExtensionList

$module_list->getExtensions();
$module_list->getExtension($extension_name);  // Current proposal in e.g. #2208429-165
$module_list->nameGetExtension($extension_name);  // New, option 1
$module_list->extensionGetExtension($extension_name);  // New, option 2, which I find awkward.

In this example, besides distinguishing classical getters from parameterized getters, we also need to distinguish extension machine name, extension human name, extension object, and extension info array. So imo the ->nameGet*() would be better than ->extensionGet*().

This would also work for parameterized setters:

  $extension_list->setFilename($extension_name, $filename) {  // Current proposal in e.g. #2208429-165
  $extension_list->nameSetFilename($extension_name, $filename);  // New, option 1

Since we are not currently doing this anywhere I am aware of, this needs a coding standards discussion before it can be applied.