Currently the LanguageConverter is enabled for all pages and can be disabled in individual pages by using __NOCONTENTCONVERT__ (or __NOCC__).[1]
At Wikisources we are considering[2] the use of Language Converter as an improvement in the current "Modernization" Javascripts[3][4], but the current use of this kind of tool at Wikisource is in a per page basis so that it is only available an option to see the modernized if the page was reviewed by some editor, which then adds the corresponding template[5][6] to the page.
For the use of LanguageConverter as the replacement for the script, we would need to be able to do that again, I mean, to show the Conversion menu only if the page was marked with the magic word.
The new magic word/behavior switch could be called something like __CONTENTCONVERT__ and __CC__, in analogy to the existent ones.
Maybe this request is related or blocked by Bug 18958, I don't know for sure.
[1] http://meta.wikimedia.org/wiki/Help:Magic_words#Other
[2] http://wikisource.org/w/index.php?title=Wikisource:Scriptorium&oldid=298863#Using_LanguageConverter_syntax_at_Wikisources
[3] http://wikisource.org/w/index.php?title=MediaWiki:Modernisation.js
[4] http://pt.wikisource.org/wiki/Usuário:Heldergeovane/Scripts/Modernisation.js
[5] http://pt.wikisource.org/wiki/Predefini%C3%A7%C3%A3o:Moderniza%C3%A7%C3%A3o_autom%C3%A1tica
[6] http://fr.wikisource.org/wiki/Mod%C3%A8le:Modernisation
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**Version**: unspecified
**Severity**: enhancement