Is Everything Metric - Auto Unit Converter safe?

Automatically adds metric conversions next to US and older British units on webpages.

This extension converts units such as feet, miles, pounds, gallons, Fahrenheit, mph, mpg, area, and volume into SI/metric equivalents. It can run automatically on pages, be toggled on or off from the toolbar, or be triggered manually with Alt+M, and it offers an options page for settings.