Where is the edge split on the new version of Blender 2.83.1

It's a bit confusing, but it is now ALT+M. M is Merge and ALT+ * is the 'opposite'.

The best thing to do if you get lost, is to use the search:

Thank you so much. You're the best

Ah someone beat me to it. :) Another way is to right click when you're editing edges in Edit Mode.

You rock as well! Thanks