This used to work, but recently (last few months, sorry can't be more specific) stopped working.
The rewrite for favicon.ico still works, and the same rewrite does work for non-Wikipedia sites.
* https://en.wikipedia.org/apple-touch-icon.png - 404 Not Found
* https://en.wikipedia.org/favicon.ico - OK
* https://en.wikipedia.org/robots.txt - OK
* https://nl.wikipedia.org/apple-touch-icon.png - 404 Not Found
* https://nl.wikipedia.org/favicon.ico - OK
* https://nl.wikipedia.org/robots.txt - OK
* https://commons.wikimedia.org/apple-touch-icon.png - OK
* https://commons.wikimedia.org/favicon.ico - OK
* https://commons.wikimedia.org/robots.txt - OK
Should be covered by <https://github.com/wikimedia/operations-puppet/blob/812f280d16acfe3083259e8dfa7ce12ebf71da87/modules/mediawiki/files/apache/sites/public-wiki-rewrites.incl#L7-L10>
```
# Configurable favicon
RewriteRule ^/favicon\.ico$ /w/favicon.php [L]
# Configurable apple-touch-icon.png
RewriteRule ^/apple-touch-icon\.png$ /w/touch.php [L]
```