A plugin that modifies the `admin_email` and `blogname` and `blog_public` options for staging sites. Typically used as a mu-plugin so I can pull down a production DB and automatically override certain values with Staging values and I don't have to remember to manually change them each time.

The core option filters:

`option_{option_name}`: Filter that runs on the option value after it has been retrieved and before it's returned.
`pre_option_{option_name}`: Filter that runs before getting the option from the DB (it 'short-circuits' the get_option call to allow plugins to override it)

Both are in `wp-includes/option.php` starting on line 40