Request for documentation of fig.mne.*

Several months ago under the discourse group I posted the question, Obtaining bad channels and annotations from command line without closing plot window.

@drammock suggested that if would like to see more documentation about fig.mne*, then perhaps I should open an issue on it and tag him.

The basic idea is that for gui development with mne, it's useful (at least it has been for me) to retrieve bad channels, annotations, etc. while the plot window is open. For example,

bads = fig.mne.info['bads']
annotations = fig.mne.inst.annotations

retrieves the currently marked bad channels and annotations.

A listing of other attributes of fig.mne would be helpful. For example, how can I retrieve the locations of vertical guides created by left-clicking on the plot background?

Start from the fig = raw.plot() example in the issue and inspect the plotting API that exposes fig.mne, including info and inst. Document the available fig.mne attributes and clarify whether vertical-guide locations can be retrieved. Done means the relevant attributes and retrieval method are described for GUI users.