I’ve spoken about this in the past, but it’s a pretty important topic, so I thought I’d bring it up again (and will likely do so again)…
One of the best ways to keep up to date with what’s happening at Eclipse is to listen in on bugzilla. Bugzilla is where bugs are reported, and where conversations concerning those bugs are recorded. You want to understand why a certain design decision is made? The answer is likely somewhere in Bugzilla.