Magnifier од Satish Mishra

Magnifier lets you hover over any content on a webpage and instantly see it enlarged in a floating lens overlay — no clicking, no zooming the whole page.

What it magnifies:

Text — reads the exact font, size, weight, and color of what's under the cursor and renders it enlarged inside the lens
Images — zooms into photos and background images with pixel-accurate centering
PDFs — open any PDF in the built-in viewer and magnify rendered pages directly
Customize the lens:

Shape — Circle for a classic loop feel, or Rectangle for a wide reading-strip view
Zoom — 1× to 10× in 0.5 steps
Size — Small, Medium, or Large
Position — Place the lens to the Left, Right, Above, Below, or Centered on the cursor
Touch support — Works on Android Firefox; the lens follows your finger
Controls:

Toggle on/off per tab from the toolbar popup
"Ctrl+M" keyboard shortcut to toggle instantly
"Escape" key to dismiss the lens
Settings sync automatically across devices via Firefox Sync
The magnifier is active only for the tab you enable it on - other open tabs are never affected. When you switch tabs the lens closes automatically. No data is collected or transmitted.