I get "Notice: Undefined variable: wgUseXVO in RawAction.php on line 96" when viewing action=raw using the latest MW 1.23 release.

In T125283#2320859, @GreenReaper wrote:

T125283-REL1_23.patch broke MediaWiki 1.23's raw action because it uses $wgUseXVO in the onView() function where it is not yet declared. This may result in a PHP Notice which breaks things served via Raw action (e.g. the JavaScript we store and serve from MediaWiki).

I suggest changing
global $wgSquidMaxage, $wgForcedRawSMaxage;
to
global $wgSquidMaxage, $wgForcedRawSMaxage, $wgUseXVO;
at the start of the onView() function.

(Originally reported by @GreenReaper at T125283#2320859.)