Two parts to this question

Does Apple provide in Lion, Mac OS X 10.7 (Build 11A511) an API that might enable a third party developer to add a sidebar to iCal 5.0 (1535)?

If not provided by Apple: what would be the best starting point for a hack?

The first that comes to mind:

• SIMBL — not specifically updated for Lion, but certainly proving itself good for many purposes.

Context

In this question I'm focused solely on the sidebar:

• primarily for a list of calendars — grouped as they were, or better than, in Snow Leopard
• with only minimal interest in mini-months, which were optional in the sidebar in Snow Leopard (it's trivially simple to switch between year, month and other views in iCal 5.x)
• integrated with iCal (not running as a separate application).

This question, not for the possibility of detaching the aqua popover — that might form a separate question.

In Apple Support Communities:

• side开发者_运维问答bar missing from iCal in Lion — seeking a third party product to restore lost functionality

I see Mac OS X v10.6 to v10.7 API Diffs and other documents, but I'm not a developer so I'm not sure of the best starting point for browsing and understanding APIs. (I have archaic ADC Online membership and more, but for my level of interest/understanding etc., I have chosen to not enrol in the Mac Developer Program.)

Thank you!

Update, February 2012

It seems that for the developer preview of Mountain Lion, Apple has restored the sidebar to iCal. Great news, if this feature makes it to release … but still, an answer to this Lion-specific question will be appreciated.