Layouts before "Mid-2013" have no way (as far as I could find out) of viewing the "Live" tab of YouTube channels, whereas layouts afterwards feature a "Live Events" drop-down in the "Videos" tab, which especially sucks for viewing channels whose content is mostly archived/live content, which cannot be accessed.
What post-"Mid-2013" layouts have in order to view live videos:

What "Early-2013" and before layouts have (notice how there is no way to view live videos):
