I code large Lua modules in my local computer, using JEdit, and I would an easier way to test them 100 times each day.
Who would benefit
Any Lua coder to try his/her code, specialy central modules which will be larger than present ones.
Also to change any large content in any external edit tools better adapted at each case : images, sounds, fonts...
Mediawiki servers able to preview a module, a page or a content.
The final validation and the Mediawiki options rest in present Mediawiki editor with all environment details.