What does the frame_offset_end/Trim Duraion (soft) mean? I've recently started making scripts to assist in my video editing, and it's already helped me out tremendously!  Now I want to make a script that automatically changes the video offset of all the selected strips by a set amount.

In doing this, I noticed a very confusing property about trimmed video clips.  For the Trim Duration (soft), the frame_offset_start of clips makes sense because it's the frame of the original clip where this cut begins.  However, the frame_offset_end seems to make absolutely no sense.  Its value is lower than the start value, but it's not the length of the clip and it's not the end frame.  When I increase the value, the clip gets shorter!  What is going on?
Hard and soft cut, and the differences between them, explained here: Video sequence editing, cutting strips