Userscript manager
A userscript manager is a type of browser extension and augmented browsing technology that provides a user interface to manage scripts. The main purpose of a userscript manager is to execute scripts on webpages as they are loaded. The most common operations performed by a userscript manager include creating, installing, organizing, deleting and editing scripts, as well as modifying script permissions (e.g. website exceptions).
Userscript managers use metadata that is embedded in scripts primarily to determine the websites they should execute on and the dependencies necessary for the scripts to run properly. Metadata can also include information that is useful to the user such as the script's name, author, description and version number.