Manual:$wgEditEncoding

From MediaWiki.org

Localization: $wgEditEncoding
Characters not explicitely converted by output encoding
Introduced in version:	pre 1.1.0
Removed in version:	still in use
Allowed values:
Default value:	""

Other settings: Alphabetical | By Function

[edit] Details

For some languages we'll want to explicitly specify which characters make it into the edit box raw or are converted in some way or another. Note that if $wgOutputEncoding is different from $wgInputEncoding, this text will be further converted to wgOutputEncoding.