In order to cut the video, I use the ripple-button (red circle) to create these cuts in the clip (green circle around the “ripple” lines).
Howver, let us say i don’t like a ripple-line that I’ve created and want to delete/undo this cut-line.
The button your highlighted is called “Split at Playhead”. When you click it, it makes a split.
If you immediately notice that you do not want a split, you can just click the “undo” button (or use the shortcut CTRL-Z).
If you decide much later that you do not want the split, there is an option to rejoin them. Right click on the left clip, and look for the “Rejoin with next clip” option. That option will only be available if the two clips are from an original split and they can be rejoined.
Someone else not English speaker also thought “Ripple” means a blank region of time also known as a gap. It is because there is an Action in Shotcut named “Ripple Delete” so it sounds like Ripple is the name of an object. However, the meaning of Ripple is explained in the Glossary of the User Guide. It it easy, right-click and choose Ripple Delete. Alternatively, you can turn on Ripple edit mode:
And drag the clip to the right of the gap leftward to close the gap.