1.2

• Adds support for MediaWiki 1.39 and 1.40. As these versions don’t use the Codex system, colors and other values will be hardcoded to sensible defaults. You can override these to match the color scheme of your skin(s) in your wiki’s CSS if needed.
• Adds a configuration option, $wgDetailsMWCollapsibleCompatibility. This can be set to false to disable all CSS and JavaScript injected by the extension, leaving all styling and behavior at the browser’s defaults.

Both changes were contributed by @alistair3149 - thanks!