Loads all WordPress/ClassicPress plugins within subdirectories of the mu-plugins directory where the name of the core plugin, the one with the plugin header, is the same as the name of the plugin directory.

To install, simply add the load-mu-plugins.php file to the mu-plugins directory of your installation. You may need to create this directory in the wp-content directory.

Then make sure directory names and file names match. For instance, out of the box the Advanced Custom Fields plugin comes as advanced-custom-fields/acf.php so ACF will not be loaded without changing the name of the directory or the file (e.g. acf/acf.php).

For purposes of keeping plugins updated it is probably best to rename mismatched directory names to the file names so that the contents of the updated plugin simply need to be replaced without renaming the plugin file.