It is dividends, interest, and realized capital gains that would appear on a 1099 if not for the fact that they were paid from (and reinvested into) a retirement account. It is not unrealized capital gain from share price increase, nor current year contributions from earned income. But whether or not this constitutes "passive income" is the gist of the question.
It is not really "locked" at all. I am over 60 so it is accessible to me any time that I choose to withdraw it. I have not needed to withdraw it as I still work and continue to have earned income, but my intention is to retire and move to Thailand and live off these investments. So I'm not really a pensioner yet, and I won't have Social Security for another 1.5 years. But my portfolio is already providing $80+k/yr in dividends, interest, and realized capital gains (not including unrealized capital appreciation from share price increases).