Very cool tool!
Two immediate thoughts: one, the naming had me confused for a while. The only place I've seen the word "yank" in computing is in Emacs context, where it means "paste", not "copy"...
Two, natural extension of this idea is "interactively select and transform data in the pipe". I think existing text editors would be natural fit for this, especially if configured with some conveniences (like field-based navigation and ability to delete everything except a particular column/line with one command). Then, you could drop such editor into a pipe using something like [0]. I'm gonna try this with terminal Emacs client at some point.
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