Adjustment Layer Strip
The Adjustment Layer strip works like a regular input file strip except for the fact, that it considers all strips below it as its input.
Real-world use cases, you want to add some last finishing color correction on top of parts of your final sequence, timeline without messing with meta strips around. Just add an adjustment layer on top and activate the color balance.
Or you can stack a primary color correction and several secondary color corrections on top of each other (probably using the new mask input for area selection).
This strip has no options.