Rosetta από Blueberry Muffin

Rosetta translates web pages in place. Markup, links and layout survive — only text nodes are replaced, and Restore puts the original back without a reload.

It only translates what you can see. Text is sent when its element is actually on screen, checked with IntersectionObserver plus Element.checkVisibility(), so a closed menu that still occupies layout isn't "visible". Opening a menu or accordion translates its contents on the spot, and dynamically rendered content is picked up as it appears. Pages that host their content in iframes work too.

Two engines, your choice:

Google Translate — any language pair, fast, but the text of the page is sent to Google's servers.
OPUS-MT (offline) — Hebrew→English only. The model runs inside your browser; no page text leaves your machine. One-time ~365 MB download, only if you ask for it, removable from the popup.

Translations are cached locally, so a string translated once is reused across pages, tabs and restarts. Also translates tooltips, placeholders, image alt text, screen-reader labels and the tab title. Work pauses while a tab is in the background, and Cancel actually cancels.

Open source: https://github.com/wlwatkins/Rosetta