I sincerely hope many more employees than they anticipate avail themselves of this opportunity.

You must have missed the details in the article. OPM has listed on their website under ‘fork’. The deadline for acceptance is 6 Feb, and the resignation will be effective at the end of September. There is no back and forth with HR; you simply reply to their email with the word ‘resign’ or you don’t and remain employed until the loyalty police come around.