TracePrint[expr] prints all expressions used in the evaluation of expr.
TracePrint[expr, form] includes only those expressions which match form.
TracePrint[expr, s] includes all evaluations which use transformation rules associated with the symbol s.
See notes for Trace.
TracePrint indents its output in correspondence with the nesting levels for lists generated by Trace.
The indentation is done using the print form defined for the object Indent[d].
TracePrint prints the forms of expressions before any of their elements are evaluated.
TracePrint does not support the TraceBackward option of Trace.
TracePrint yields only the forward part of the output specified by the option setting TraceAbove -> All.
TracePrint[expr] returns the result of evaluating expr.
See The Mathematica Book: Section 2.5.10.