2.1.1219 Part 4 Section 4.6.87, tnLst (Time Node List)
a. The standard states that the child list of the tnLst element is unbounded.
PowerPoint does not support more than one child element in the tnLst.
b. The standard states that the anim, animClr, animEffect, animMotion, animRot, animScale, audio, cmd, excl, seq, set, and video elements are valid children of the tnLst element.
PowerPoint does not allow these elements to be children of the tnLst element.
c. The standard places no restrictions on the time nodes at a depth of five in the timing tree defined by the child element of the tnLst element.
The child of this element is the root time node in the timing tree. A node at depth 5 in the timing tree shall meet at least one of the following criteria:
Be a behavior node (a node with cBhvr (“[ECMA-376] Part 4 §4.6.22; cBhvr Common Behavior)”) as a child element) and contain a valid reference to a <tgtEl>.
Have at least one child element that is a behavior node, the first of which shall contain a valid reference to a <tgtEl>.