Google slows down YouTube for users who don’t use the Silicon Valley giant’s own Chrome browser, according to an executive from Mozilla, which makes the Firefox browser.

In a series of tweets, the executive claimed Google was intentionally slowing down YouTube on Mozilla’s browser Firefox and Microsoft’s browser Edge.

“YouTube page load is 5x slower in Firefox and Edge than in Chrome because YouTube’s Polymer redesign relies on the deprecated Shadow DOM v0 API only implemented in Chrome,” claimed Mozilla Technical Program Manager Chris Peterson. “You can restore YouTube’s faster pre-Polymer design with this Firefox extension.”

YouTube page load is 5x slower in Firefox and Edge than in Chrome because YouTube's Polymer redesign relies on the deprecated Shadow DOM v0 API only implemented in Chrome. You can restore YouTube's faster pre-Polymer design with this Firefox extension: https://t.co/F5uEn3iMLR — Chris Peterson (@cpeterso) July 24, 2018

“YouTube serves a Shadow DOM polyfill to Firefox and Edge that is, unsurprisingly, slower than Chrome’s native implementation,” he continued. “On my laptop, initial page load takes 5 seconds with the polyfill vs 1 without. Subsequent page navigation perf is comparable.”

YouTube serves a Shadow DOM polyfill to Firefox and Edge that is, unsurprisingly, slower than Chrome's native implementation. On my laptop, initial page load takes 5 seconds with the polyfill vs 1 without. Subsequent page navigation perf is comparable. — Chris Peterson (@cpeterso) July 24, 2018