Adding a new plugin
An extensible architecture allows for providing new plugin types (for reading and writing different firmware) as well as ways quirk their behavior.
You can find more information about the architecture in the developers section of the fwupd website.
If you have a firmware specification and would like to see support in this project, please file an issue and share the spec. Patches are also welcome.
Some plugins may be able to influence the behavior of other plugins. This includes things like one plugin turning on a device, or providing missing metadata to another plugin.
The ABI for these interactions is defined in: https://github.com/hughsie/fwupd/blob/master/src/fu-device-metadata.h
All interactions between plugins should have the interface defined in that file.