This report is regarding libwebkit2gtk-4.1 (2.38.3) via Eolie browser on Linux. Starting with the 4.1 API, WebKit no longer recognizes "WEBKIT_DISABLE_COMPOSITING_MODE" as a system-wide environment variable, such as in an environment.d conf file. libwebkit2gtk-4.0 picks up on the system-wide environment variable and disables compositing, so this appears to be a change between the 4.0 and 4.1 API. Please have WebKit recognize this system-wide environment variable. Compositing on PowerPC Linux systems results in severely incorrect color rendering.
This environment variable is still respected. The only difference between -4.0 and -4.1 is networking, not graphics.