Transient is a plugin that amplifies or attenuates the transients on an audio track. The transients are the parts of sound that change a lot in amplitude and in frequency, for example the attack of the sounds, but not only.
The plugin uses an innovative principle that enables original use, for example when processing voice recordings. In short, it processes in the spectral domain to separate the sound in two parts, transient and not transient parts, and provides a knob to mix these two parts to get the result.
For a more standard transient shaper, please have a look at the Shaper plugin.