If they're just meaning should they test certain popular plugins before releasing a new versin of WP, then I saw yet. Although I assume that is already done anyway.

If it is a question between including something in the core, or bundling a plugin, I saw stick it in the core. I don't see much point in having something as a plugin when it's bundled in anyway. If a bundled plugin is broken, then the core is broken since the plugin is effectively part of the core anyway (if it is bundled) ... I'm not sure that entirely makes sense, but hopefully you can decipher my gibberish.

My point is ... if you are going to bundle them as plugins, they may as well be in core anyway. Although I'm still not sure that is the question they're asking.