Is there a way to duplicate an entire video track?

I want to play 2 duplicate tracks on top of each other, with one track slightly modified (some portions cropped, etc.)

Is there a way I can copy and paste an entire video track consisting of multiple already-editted clips?

Not in one time by Copy&Paste in the same project AFAIK, but…[TM], it should work, if you make it in a separate MLT project., because you can import a MLT project as clip…

You can import an entire project as a clip? How…?!

Menu -> File -> Open MLT as Clip.
The only thing is, IMHO, that Shotcut cannot be used in multi instances, so you need to load every time, if you want to change something (for example).

Wow it worked! Thanks a lot

But beware editing the MLT file after importing as clip, it will take effect.