About Responsive-xili child theme:

The folder content:

recursive-xili folder

recursive-xili folder

File by file :
footer.php contains the new signature,
functions-xili folder contains functions to personalize by example search form,
functions.php contains important functions to built the child and the admin settings UI, v1.1 language link added in post-meta
home.php is tiny modified to be full multilingual for the default screen set in theme options,
page.php and single.php:
v1: Filtered breadcrump, a template tag is added under title to link to the other post in other languages.
v1.1: Filtered breadcrump
searchform.php is adapted to include buttons for sub-selection according language.
style.css is the core file of the child theme linking to the parent theme.
xili-css folder contains style for admin side.

As this child-theme example,

The trilogy of xili-language plugins for WordPress is available for free under license GPL2 and can be downloaded from the WP Plugin repository (as zip archive, as source code on SVN), a Read Me documentation, a Forum and a Tracs-Log etc. is available for help.

As a results of more than 5 years (meaning thousand of hours) of hard working, researching and information gathering we are able and proud to offer one of the best available multi-language WP plugin solution available as from our point of view.
The plugin in the current version is a kind of our response to WordPress and it’s php, mysql, javascript,it’s experience and know-how, its upgrade from version 2.3 to the current version 3.5.1 and the new functions it has brought along.

It has a collaborative approach containing contributions and feedback from users. Allowing continuously development and bugfixing with a lot of and improvements of the source code which remains open.
Some users and webmasters take an active part in the project by testing, translating or sharing their experiences (by writing posts containing how to’s, explaining features, and writing tutorials etc.)

This trilogy of plugins is a none commercial product and follows common rules for a free Project and is offered as is. According to this, our support in regards to this free plugin will be offered without any guarantee or fixed time lines and processed by our own priorities at our best efforts. For this reason moaners are not welcome.

After discovering the opportunities that the “XILI plugins” are offering and sharing our knowledge and expertise, some users asked us to provide, individual support and services as well as customized developments, especially in commercial and professional environments. Our consulting and individual development will be quoted on an hourly based rate and will be settled on an individual contract of work. Non profit organization are also invited to write testimonials and tutorials about the plugin.

Michel from dev.xiligroup.com