As this project originates from the German-speaking community's Technical Wishlist, there was an additional feedback round on German Wikipedia & in German language.

Two Column Edit Conflict View - very rough visualization of the functionality

Welcome to the Two Column Edit Conflict View testing!

About Two Column Edit Conflict View

Two Column Edit Conflict View is a new interface for the edit conflict resolution page and it has been a beta feature on all wikis for more than 5 months now. It highlights differences between the editor's and the conflicting change directly in the text field for an easy possibility to copy and paste desired pieces of the text and resolving the conflict.

More infos:

Testing with the test page

Edit conflict simulation under real life conditions

As edit conflicts don't occur very often, options to test the feature under real life conditions are rare. Therefore we've implemented a temporary test page, where edit conflicts can be simulated under real life conditions without messing anything up.

We were asking for feedback on the new Two Column Edit Conflict interface from October 12 to Nov 09 2017. A brief summary of the main points mentioned can be found here. The team is now looking into the feedback in detail and is discussing possible next steps. Thanks for everyone who participated in this feedback round!

Simulation page for the first beta version of the Two-Column Edit Conflict feature

The test page is no longer available. Its functionality is documented in a video.

How the test worked

Enable the Two Column Edit Conflict View beta feature in your user preferences on any wiki
Go to Special:SimulateTwoColEditConflict]] (inactive)
Add the title of any non-protected page you want to test with into the field
Click "show edit page" to open the edit window
Make some changes (e.g., minor, but many changes ...)
Click "create conflict"
- When you edit the text, this creates your edit -> this is half of the conflict
- The test page makes random changes to the page, too -> this creates the edit that you are conflicting with. Please note: In case you are not making any changes by yourself, the test page still will add random changes to create the other half of the conflict.
View your changes and the conflicting changes in the Two Column Edit Conflict screen and solve the edit conflict. We're especially interested in your experiences with the workflow and usability of the feature and if you encounter any bugs/problems!
Click "simulate save changes"

Feedback

The feedback link on the test page will bring you to the talk page of this page where we have prepared some questions we're interested in getting your input on. If you want to read through the general feedback we've received on Two Column Edit Conflict View for the last months, please see the comments on the central feedback page on mw.org.

Thank you very much for your time!