What the renderer's viewport reaches. Run in URL Inspection and read the rendered HTML: the script writes what it saw below, each block says whether it entered the viewport, and Page resources lists which loading="lazy" images were requested (?y= down the page, ?x= across the strip). ?h= sets how tall the page is, and ?fill=text makes it that tall with paragraphs of text instead of empty blocks (&cv=auto or &cv=hidden gives that text content-visibility).
viewport: script did not run
entered the viewport: none