In current Mediawiki 1.23, the skin autodiscovery mechanism used by this skin is deprecated. See Manual:Skin autodiscovery. Will this skin be adopted to this change anytime soon, or has development been ceased?
Topic on Skin talk:Cavendish
That's something I'm also wondering. But as it seems that there has been no reply to your question I presume that the skin is deprecated. I'm trying myself to get this autodiscovery disabled but haven't succeeded so far.
Afte trying and trying by splitting up the skin in different files I couldn't get it to work. What finally seemed to work was:
I had created a new directory $IP/skins/Cavendish where I put the contents of $IP/skins/cavendish
Then copies Cavendish.php from $IP/skins to $IP/skins/Cavendish and added the following line:
$wgValidSkinNames['cavendish'] = 'Cavendish';
In $IP/LocalSettings.php I added
require_once( "$IP/skins/Cavendish/Cavendish.php" );
Finally moved/renamed $IP/skins/Cavendish.php to a file with another extension.
Now error_log doesn't give lines saying that I use a skin with autodiscovery.
Still, I would like to split things up as describe in https://gerrit.wikimedia.org/r/#/c/138795/ but that didn't seem to work. We also use part of another skin though, which I haven't included in the above modifications.
You also will have to fiddle with the files themselves and not just moving them over to other places. This is a nice how-to: Skin autodiscovery migration guide. Not sure if it works for this skin though.
Yep, I did and in the end converted Cavendish to a new skin which will be internally used, as there were also MonoBook-related things.