How this differs from your browser's zoom/accessibility settings

Your phone and browser already have a font-size or zoom setting. This tool exists alongside those, not instead of them, because they solve a different problem:

• Browser/OS zoom and font-size settings apply everywhere, all the time. Once you turn them up, every site is bigger, whether it needed it or not. And pinch/page zoom usually just magnifies the whole page like a photocopier enlargement — including its width — so you end up scrolling sideways to read a single line.
• Text Size Adjuster only changes the sites you adjust. Tap + on a page that's too small to read. The extension remembers that size for that site (you can turn this off in its options); the userscript and the website version reset on the next page load. The text reflows to fit the screen width you already have — no sideways scrolling.

In short: turn up your phone's accessibility settings if everything is too small for you all the time. Reach for this tool when particular sites' text is uncomfortably small.