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Child-to-parent CPOWs
CPOWs that refer to objects in the parent (chrome) process.
Chrome process (also called the parent process)
The operating system process that runs the Firefox UI, including the toolbar, dialog boxes, and features like session restoration. All add-on code that doesn't run in frame scripts runs here.
Content process (also called the child process)
The operating system process that runs web content, in multiprocess Firefox. Code for frame scripts runs in this process.
Content scripts
Deprecated term for frame scripts.
CPOW stands for Cross Process Object Wrapper. A CPOW gives chrome code synchronous access to content objects, as a migration aid. See more about CPOWs.
Frame scripts
When chrome code needs to interact with web content, it factors the code that needs to access content into separate scripts, and loads them into the content process. These separate scripts are called frame scripts. We used to call these scripts "content scripts" but have deprecated that term.
Message manager
Message managers enable chrome code to load frame scripts into content processes, and communicate with them using a message-passing API. See more about message managers.
Parent-to-child CPOWs
CPOWs that refer to objects that live in the child (content) process.