Is WindowSizer safe?

Resizes the browser window using custom presets from a toolbar menu or shortcut keys.

This extension lets you create, edit, reorder, back up, and restore window-size presets with custom names, widths, and heights. You can apply presets from the toolbar popup or with customizable keyboard shortcuts, and you can quick-fill preset values from the current window size. It uses storage permission to save settings and supports Firefox Sync for backups.