GitHub Resizer от R0GGER

GitHub Resizer puts a slider in your Firefox toolbar that lets you choose exactly how wide GitHub pages should be - anywhere between GitHub's native 1280 px layout and the full width of your browser window, in 1 % steps.

Most "wide GitHub" extensions are an on/off switch: either you get the default narrow layout, or you get the full screen. GitHub Resizer answers a different question: how wide? Pick 25 % for a comfortable reading width on a 4K monitor, 50 % on an ultrawide so code blocks stay readable, or 100 % to fill the entire screen.

Features

• Smooth slider from 0 % (default GitHub) to 100 % (full viewport) in 1 % steps.
• Quick presets: 25 %, 50 %, 75 %, 100 %.
• Live updates - your setting is applied to every open GitHub tab instantly, without a page reload.
• Cross-device sync - your chosen width follows you to other computers via your Firefox account (storage.sync), with a local fallback.
• Safe on small screens - on viewports up to 1280 px the extension does nothing, so GitHub looks identical to its default layout.
• Works on modern GitHub - also widens the inner content column on the new Primer-based GitHub pages, so the page doesn't end up wide-on-the-outside but narrow-in-the-middle.
• Keeps READMEs and other markdown content responsive instead of capping them at a fixed width.

Where it works

• github.com (repos, pull requests, issues, code view, README, etc.)
• gist.github.com

GitHub Enterprise and custom-domain GitHub installs are not currently supported.

Permissions

• Access your data for github.com and gist.github.com - needed to inject the CSS that widens the layout.
• Storage - needed to remember your chosen width and sync it across devices.

Privacy

No tracking, no analytics, no network requests. The only thing the extension ever stores is a single number between 0 and 100 - your chosen width - in Firefox's own storage. Nothing leaves your browser except via Firefox's built-in account sync (if you have it enabled).