Ever since I've had my prius I noticed a dangling hose? wire? Haven't thought much about it since it doesn't effect performance, but what exactly is this and how do I fix it?
But at least you should try to attach the dropping down(dangling) portion to the under chases to prevent accident as if you drive over somewhere with object pointing out will catch the dangling part. Either the cable got broken or even damage the rear brake. Don't leave it. Fix it. Use glue or some way to make it attach to the under chases. Or go to a garage to fix which is a easy job for them and should not spend much.
Next time you park on a hill, you may regret not getting it fixed! You really need to fix, not blow it off, this! Really!
I'll get it adjusted the way it was originally. Was checking here to make sure it was not an electrical wire or fuel hose to be concerned about.