-<h2>Stretch</h2>
-
-<p>FIXME. Optional. What happens when disabled? Won’t match the current timeline
-tempo: START THE SECTION WITH THIS: ARDOUR ALWAYS MATCHES CURRENT SESSION
-TEMPO, SO TEMPO RAMPS WILL WORK FOR CLIPS</p>
+<h2>Stretching</h2>
+
+<p>
+ When you load an audio clip into a trigger slot, Ardour applies some
+ heuristics to estimate its temo in beats per minute. Unless a metadata
+ in the file source provides information,
+ <a href="https://github.com/breakfastquay/minibpm">minibpm</a> is used
+ to analyze and detect the file's BPM.
+</p>
+
+<p>
+ After tempo is estimated, the clip is time-stretched to match the
+ session's tempo map. This means that should session's tempo change over
+ time (in either ramped or constant mode), all audio clips will be
+ re-stretched to accomodate for that.
+</p>
+
+<p>
+ Disabling stretching when original clip's tempo doesn't match that of the
+ session will most of the times make the clip audibly go out of sync with
+ the beat.
+</p>