I have installed some wp page speed optimization plugins to my website. Now the website works faster, however one of the plugins adds its own file name ending, like this one: styles.css.pagespeed.cf.M0Q5l-FwhO.css. I tried disabling all plugins I thought might be somehow related to the question, but nothing changed. Also, the plugin modifies all media files names same way, e.g.: picture.jpg.pagespeed.F0K2c-zkg8.jpg

Has anyone encountered such problem before?