Blaze is Windows only and embeds IronPython for user scripting. It is open source, and the latest release is from Friday (September 18th) so it is under active development. Blaze is available as an installer or a portable version that can be used without installing.
There isn't yet a manual for developers. However, it's pretty easy to extend Blazes functionality with IronPython. Take a look on Scripts Folder. There are already two scripts build in which you can get inspiration from.Not only can you write new automator scripts in IronPython, but macros you record will be saved as IronPython scripts:
To use the ContextLib, there is an outadated .chm file in Blaze's instalaction directory, in the "Docs" folder. It should work just fine for most common features. In the future I will update this documentation properly.
Blaze has the ability to record Adaptive Macros, which are macros that can adapt to new window positions. These macros also have the advantage of being recorded to IronPython files (.py), making them really easy to edit with notepad.Not so sure about the advice to use Notepad for editing Python files though...