docs: mention variability of media codecs between platforms (#32569)

References #32558.

docs/src/browsers.md

@@ -459,9 +459,13 @@ Google Chrome and Microsoft Edge respect enterprise policies, which include limi
 
 Playwright's Firefox version matches the recent [Firefox Stable](https://www.mozilla.org/en-US/firefox/new/) build. Playwright doesn't work with the branded version of Firefox since it relies on patches.
 
+Note that availability of certain features, which depend heavily on the underlying platform, may vary between operating systems. For example, available media codecs vary substantially between Linux, macOS and Windows.
+
 ### WebKit
 
-Playwright's WebKit is derived from the latest WebKit main branch sources, often before these updates are incorporated into Apple Safari and other WebKit-based browsers. This gives a lot of lead time to react on the potential browser update issues. Playwright doesn't work with the branded version of Safari since it relies on patches. Instead, you can test using the most recent WebKit build. Note that availability of certain features, which depend heavily on the underlying platform, may vary between operating systems.
+Playwright's WebKit is derived from the latest WebKit main branch sources, often before these updates are incorporated into Apple Safari and other WebKit-based browsers. This gives a lot of lead time to react on the potential browser update issues. Playwright doesn't work with the branded version of Safari since it relies on patches. Instead, you can test using the most recent WebKit build.
+
+Note that availability of certain features, which depend heavily on the underlying platform, may vary between operating systems. For example, available media codecs vary substantially between Linux, macOS and Windows. While running WebKit on Linux CI is usually the most affordable option, for the closest-to-Safari experience you should run WebKit on mac, for example if you do video playback.
 
 ## Install behind a firewall or a proxy