Blur or Redact a Region

Only the solid block truly removes anything. Blur and pixelation are reversible in the sense that matters: both leave a statistical trace of the original, and recovering pixelated text from a known font is a documented attack. They are fine for tidying a photo and wrong for hiding an address, a face or an account number. The solid block overwrites those pixels outright, and the exported file is a fresh canvas render, so the original pixels are not carried along in the output.