After doing a research I found no official explanation neither from Cydia itself or from Saurik, however I am confident enough to say that the SHSH Blobs listing get something to do with the upcoming A4 untethered userland jailbreak which already finished and handed to the Chronic Dev-team for testing purpose by Pod2G.
Or for giving the access for iOS downgrading, just in case a user doing something accidental that put him on the upgrade trap. This could mean, from now and then, we can downgrade our iOS using Cydia server -- or at least at iOS 5.0.1 -- just like the old days when iOS 4 downgrading was around on Cydia.
With that thought in mind, then men behind Cydia are currently working for iOS 5 firmware downgrade to bring us the easier downgrade process with Cydia as the server.
However the listing must be put by a reason. Right?
Recommended readings about downgrading iOS firmwares:
- How To Downgrade iOS 5.0.1 To iOS 5 Using iFaith V1.4
- Downgrade iOS 5 To iOS 4.3.3 On iPad 2, iPhone 4 For Untethered Jailbreak With TinyCFW