Sync Now, and Endless Scrolling Through Your Subscriptions
Two changes to the screen where you pick which channels to add.
Sync now. RandomYV keeps a copy of your YouTube subscriptions rather than asking YouTube every time you open the page, which is what makes that page load quickly. The cost is that a channel you subscribed to five minutes ago is not there yet. There is now a Sync now button that discards the copy and fetches your subscriptions again, so a channel you just subscribed to shows up straight away.