This has already been mentioned here:
There hasn't been a change yet it seems.
Do we really need live-cd, live-usb, livedvd, and live-environment?
It seems that is a bit of overkill.
I can understand there is some sort of separation, because of what media the live environment is on, but these could really all be migrated together into one tag. For instance live-boot, live or into an existing one.
live-media
probably makes more sense than live-boot.